diff --git a/src/brmember.scm b/src/brmember.scm
index 496dc96..cb065f4 100644
--- a/src/brmember.scm
+++ b/src/brmember.scm
@@ -87,6 +87,8 @@
 
   brmember-spec-fee
 
+  brmember-age
+
   brmember-tests!
   )
 
@@ -492,6 +494,18 @@
 	       #f))
 	 #f)))
 
+ (define (brmember-age mr)
+   (let ((born (brmember-info mr 'born #f)))
+     (if born
+	 (let ((lst (string-split born "-")))
+	   (if (null? lst)
+	       #f
+	       (let ((y (string->number (car lst))))
+		 (if y		     
+		     (- (current-year) y)
+		     #f))))
+	 #f)))
+
  ;; Self-tests
  (define (brmember-tests!)
    (run-tests
diff --git a/src/cal-period.scm b/src/cal-period.scm
index ea1cf3d..447f563 100644
--- a/src/cal-period.scm
+++ b/src/cal-period.scm
@@ -26,460 +26,464 @@
 (declare (unit cal-period))
 
 (module
- cal-period
- (
-  *current-month*
-  *current-day*
-
-  set-current-month!
-  set-current-day!
-
-  with-current-month
-  with-current-day
-  
-  make-cal-period
-
-  cal-period-since
-  cal-period-before
-  cal-period-scomment
-  cal-period-bcomment
-
-  set-cal-period-scomment
-  
-  period-markers->cal-periods
-  
-  cal-periods-duration
-  
-  cal-month-in-period?
-  cal-month-in-periods?
-
-  cal-month-find-period
-
-  cal-day-in-period?
-  cal-day-in-periods?
-  
-  cal-periods->string
-  cal-periods-match
-  
-  make-cal-period-lookup-table
-  lookup-by-cal-period
-
-  cal-ensure-month
-  cal-ensure-day
-  
-  cal-period-tests!
-  )
-
- (import scheme
-	 (chicken base)
-	 (chicken sort)
-	 (chicken time)
-	 (chicken time posix)
-	 (chicken format)
-	 (chicken string)
-	 cal-month
-	 testing
-	 util-tag
-	 cal-day)
-
- ;; Type tag
- (define TAG-CAL-PERIOD (make-tag CAL-PERIOD))
-
- ;; Current month - if changed, we get the actual state for given month.
- (define *current-month*
-   (make-parameter
-    (let ((d (seconds->local-time (current-seconds))))
-      (make-cal-month (+ 1900 (vector-ref d 5))
-		      (+ (vector-ref d 4) 1)))))
-
- ;; Current month - if changed, we get the actual state for given month.
- (define *current-day*
-   (make-parameter
-    (let ((d (seconds->local-time (current-seconds))))
-      (make-cal-day (+ 1900 (vector-ref d 5))
-		    (+ (vector-ref d 4) 1)
-		    (vector-ref d 3)))))
-
- ;; Changes both current-month and current-day based on given month
- (define (set-current-month! m)
-   (*current-month* m)
-   (*current-day* (cal-ensure-day m)))
-
- ;; Changes both current-day and current-month based on given day
- (define (set-current-day! d)
-   (*current-day* d)
-   (*current-month* (cal-ensure-month d)))
-
- ;; Parameterizes both current-month and current-day based on given
- ;; month
- (define-syntax with-current-month
-   (syntax-rules ()
-     ((_ ms body ...)
-      (let ((m ms))
-	(parameterize ((*current-month* m)
-		       (*current-day* (cal-ensure-day m)))
-	  body ...)))))
-
- ;; Parameterizes both current-day and current-month based on given
- ;; day
- (define-syntax with-current-day
-   (syntax-rules ()
-     ((_ ds body ...)
-      (let ((d ds))
-	(parameterize ((*current-day* d)
-		       (*current-month* (cal-ensure-month d)))
-	  body ...)))))
-
- ;; Creates a new period value with optional since and before
- ;; comments.
- (define (make-cal-period since before . args)
-   (let ((scomment (if (not (null? args)) (car args) #f))
-	 (bcomment (if (and (not (null? args))
-			    (not (null? (cdr args))))
-		       (cadr args)
-		       #f)))
-     (list TAG-CAL-PERIOD since before scomment bcomment)))
-
- ;; Simple accessors
- (define cal-period-since cadr)
- (define cal-period-before caddr)
- (define cal-period-scomment cadddr)
- (define cal-period-bcomment (compose cadddr cdr))
-
- ;; Direct updater
- (define (set-cal-period-scomment p c)
-   (list TAG-CAL-PERIOD
-	 (cal-period-since p)
-	 (cal-period-before p)
-	 c
-	 (cal-period-bcomment p)))
-
- ;; Type predicate
- (define (cal-period? p)
-   (and (pair? p)
-	(eq? (car p)
-	     TAG-CAL-PERIOD)))
-
- ;; Month subtype predicate
- (define (cal-period-month? p)
-   (and (cal-period? p)
-	(cal-month? (cal-period-since p))
-	(cal-month? (cal-period-before p))))
-
- ;; Day subtype predicate
- (define (cal-period-day? p)
-   (and (cal-period? p)
-	(cal-day? (cal-period-since p))
-	(cal-day? (cal-period-before p))))
-
- ;; Validation
- (define (cal-period-valid? p)
-   (and (pair? p)
-	(eq? (car p)
-	     TAG-CAL-PERIOD)
-	(let ((since (cal-period-since p))
-	      (before (cal-period-before p)))
-	  (or (and (cal-month? since)
-		   (cal-month? before)
-		   (cal-month<=? since before))
-	      (and (cal-day? since)
-		   (cal-day? before)
-		   (cal-day<=? since before))))))
-
- ;; Sorts period markers (be it start or end) chronologically and
- ;; returns the sorted list.
- (define (sort-period-markers l)
-   (sort l
-	 (lambda (a b)
-	   (cal-day/month<? (cadr a) (cadr b)))))
-
- ;; Converts list of start/stop markers to list of pairs of months -
- ;; periods. The markers are lists in the form (start/stop cal-month).
- (define (period-markers->cal-periods l)
-   (let loop ((l (sort-period-markers l))
-	      (ps '())
-	      (cb #f))
-     (if (null? l)
-	 (list #t
-	       (if cb
-		   (reverse (cons (make-cal-period (car cb) #f (cadr cb)) ps))
-		   (reverse ps))
-	       ""
-	       -1)
-	 (let* ((marker (car l))
-		(rmt (if cb 'stop 'start))
-		(mtype (car marker))
-		(month (cadr marker))
-		(line-number (if (null? (cddr marker))
-				 #f
-				 (caddr marker)))
-		(comment (if (and line-number
-				  (not (null? (cdddr marker))))
-			     (cadddr marker)
-			     #f)))
-	   (if (eq? mtype rmt)
-	       (if cb
-		   (loop (cdr l)
-			 (cons (make-cal-period (car cb) month (cadr cb) comment) ps)
-			 #f)
-		   (loop (cdr l)
-			 ps
-			 (list month comment)))
-	       (list #f
-		     (reverse ps)
-		     (sprintf "Invalid start/stop sequence marker ~A" marker)
-		     line-number))))))
-
- ;; Returns duration of period in months. Start is included, end is
- ;; not. The period contains the month just before the specified end.
- (define (cal-period->duration p)
-   (let* ((b (cal-period-since p))
-	  (e (cal-period-before p))
-	  (e- (if e e (*current-month*))))
-     (cal-month-diff b e-)))
-
- ;; Returns sum of periods lengths.
- (define (cal-periods-duration l)
-   (apply + (map cal-period->duration l)))
-
- ;; True if month belongs to given month period - start inclusive, end
- ;; exclusive.
- (define (cal-month-in-period? p . ml)
-   (let ((m (if (null? ml)
-		(*current-month*)
-		(cal-ensure-month (car ml))))
-	 (before (cal-ensure-month (cal-period-before p) #t))
-	 (since (cal-ensure-month (cal-period-since p))))
-     (and (or (not before)
-	      (cal-month<? m before))
-	  (not (cal-month<? m since)))))
-
- ;; Returns true if given month is in at least one of the periods
- ;; given. Defaults to current month.
- (define (cal-month-in-periods? ps . ml)
-   (let ((m (if (null? ml)
-		(*current-month*)
-		(car ml))))
-     (let loop ((ps ps))
-       (if (null? ps)
-	   #f
-	   (if (cal-month-in-period? (car ps) m)
-	       #t
-	       (loop (cdr ps)))))))
-
- ;; Returns true if given month is in at least one of the periods
- ;; given. Defaults to current month.
- (define (cal-month-find-period ps . ml)
-   (let ((m (if (null? ml)
-		(*current-month*)
-		(car ml))))
-     (let loop ((ps ps))
-       (if (null? ps)
-	   #f
-	   (if (cal-month-in-period? (car ps) m)
-	       (car ps)
-	       (loop (cdr ps)))))))
-
- ;; Checks whether given day belongs to day or month period
- (define (cal-day-in-period? p . dl)
-   (let ((d (if (null? dl)
-		(*current-day*)
-		(cal-ensure-day (car dl))))
-	 (before (cal-ensure-day (cal-period-before p)))
-	 (since (cal-ensure-day (cal-period-since p))))
-     (and (or (not before)
-	      (cal-day<? d before))
-	  (not (cal-day<? d since)))))
-
- ;; Returns true if the day belongs to at least one period
- (define (cal-day-in-periods? ps . dl)
-   (let ((d (if (null? dl)
-		(*current-day*)
-		(cal-ensure-day (car dl)))))
-     (let loop ((ps ps))
-       (if (null? ps)
-	   #f
-	   (if (cal-day-in-period? (car ps) d)
-	       #t
-	       (loop (cdr ps)))))))
-
- ;; Returns string representing a month period with possibly open end.
- (define (cal-period->string p)
-   (sprintf "~A..~A"
-	    (cal-day/month->string (cal-period-since p))
-	    (cal-day/month->string (cal-period-before p))))
-
- ;; Returns a string representing a list of periods.
- (define (cal-periods->string ps)
-   (string-intersperse
-    (map cal-period->string ps)
-    ", "))
-
- ;; Finds a period the month matches and returns it. If no period
- ;; matches, it returns #f.
- (define (cal-periods-match ps .  ml)
-   (let ((m (if (null? ml) (*current-month*) (car ml))))
-     (let loop ((ps ps))
-       (if (null? ps)
-	   #f
-	   (if (cal-month-in-period? (car ps) m)
-	       (car ps)
-	       (loop (cdr ps)))))))
-
- ;; Creates lookup table from definition source
- (define (make-cal-period-lookup-table source)
-   (let loop ((lst source)
-	      (res '())
-	      (prev #f))
-     (if (null? lst)
-	 (reverse
-	  (cons (cons (make-cal-period (apply make-cal-month (car prev)) #f)
-		      (cdr prev))
-		res))
-	 (loop (cdr lst)
-	       (if prev
-		   (cons (cons (make-cal-period (apply make-cal-month (car prev))
-						(apply make-cal-month (caar lst)))
-			       (cdr prev))
-			 res)
-		   res)
-	       (car lst)))))
-
- ;; Looks up current month and returns associated definitions
- (define (lookup-by-cal-period table)
-   (let loop ((lst table))
-     (if (null? lst)
-	 #f
-	 (if (cal-month-in-period? (caar lst))
-	     (cdar lst)
-	     (loop (cdr lst))))))
-
- ;; Wrapper that accepts either day or month and returns testable month
- (define (cal-ensure-month v . stop?s)
-   (if v
-       (if (cal-month? v)
-	   v
-	   (if (cal-day? v)
-	       (apply cal-day->month v stop?s)
-	       #f))
-       #f))
-
- ;; Ensures day for checking the periods
- (define (cal-ensure-day v)
-   (if v
-       (if (cal-day? v)
-	   v
-	   (if (cal-month? v)
-	       (make-cal-day (cal-month-year v)
-			     (cal-month-month v)
-			     1)
-	       #f))
-       #f))
-
- ;; Performs self-tests of the period module.
- (define (cal-period-tests!)
-   (run-tests
     cal-period
-    (test-equal? sort-period-markers
-		 (sort-period-markers
-		  `((start ,(make-cal-month 2023 1))
-		    (stop ,(make-cal-month 2022 10))
-		    (start ,(make-cal-month 2022 3))))
-		 `((start ,(make-cal-month 2022 3))
-		   (stop ,(make-cal-month 2022 10))
-		   (start ,(make-cal-month 2023 1))))
-    (test-equal? period-markers->cal-periods
-	         (period-markers->cal-periods
+    (
+     current-year
+     *current-month*
+     *current-day*
+
+     set-current-month!
+     set-current-day!
+
+     with-current-month
+     with-current-day
+  
+     make-cal-period
+
+     cal-period-since
+     cal-period-before
+     cal-period-scomment
+     cal-period-bcomment
+
+     set-cal-period-scomment
+  
+     period-markers->cal-periods
+  
+     cal-periods-duration
+  
+     cal-month-in-period?
+     cal-month-in-periods?
+
+     cal-month-find-period
+
+     cal-day-in-period?
+     cal-day-in-periods?
+  
+     cal-periods->string
+     cal-periods-match
+  
+     make-cal-period-lookup-table
+     lookup-by-cal-period
+
+     cal-ensure-month
+     cal-ensure-day
+  
+     cal-period-tests!
+     )
+
+  (import scheme
+	  (chicken base)
+	  (chicken sort)
+	  (chicken time)
+	  (chicken time posix)
+	  (chicken format)
+	  (chicken string)
+	  cal-month
+	  testing
+	  util-tag
+	  cal-day)
+
+  ;; Type tag
+  (define TAG-CAL-PERIOD (make-tag CAL-PERIOD))
+
+  (define (current-year)
+    (cal-month-year (*current-month*)))
+
+  ;; Current month - if changed, we get the actual state for given month.
+  (define *current-month*
+    (make-parameter
+     (let ((d (seconds->local-time (current-seconds))))
+       (make-cal-month (+ 1900 (vector-ref d 5))
+		       (+ (vector-ref d 4) 1)))))
+
+  ;; Current month - if changed, we get the actual state for given month.
+  (define *current-day*
+    (make-parameter
+     (let ((d (seconds->local-time (current-seconds))))
+       (make-cal-day (+ 1900 (vector-ref d 5))
+		     (+ (vector-ref d 4) 1)
+		     (vector-ref d 3)))))
+
+  ;; Changes both current-month and current-day based on given month
+  (define (set-current-month! m)
+    (*current-month* m)
+    (*current-day* (cal-ensure-day m)))
+
+  ;; Changes both current-day and current-month based on given day
+  (define (set-current-day! d)
+    (*current-day* d)
+    (*current-month* (cal-ensure-month d)))
+
+  ;; Parameterizes both current-month and current-day based on given
+  ;; month
+  (define-syntax with-current-month
+    (syntax-rules ()
+      ((_ ms body ...)
+       (let ((m ms))
+	 (parameterize ((*current-month* m)
+			(*current-day* (cal-ensure-day m)))
+	   body ...)))))
+
+  ;; Parameterizes both current-day and current-month based on given
+  ;; day
+  (define-syntax with-current-day
+    (syntax-rules ()
+      ((_ ds body ...)
+       (let ((d ds))
+	 (parameterize ((*current-day* d)
+			(*current-month* (cal-ensure-month d)))
+	   body ...)))))
+
+  ;; Creates a new period value with optional since and before
+  ;; comments.
+  (define (make-cal-period since before . args)
+    (let ((scomment (if (not (null? args)) (car args) #f))
+	  (bcomment (if (and (not (null? args))
+			     (not (null? (cdr args))))
+			(cadr args)
+			#f)))
+      (list TAG-CAL-PERIOD since before scomment bcomment)))
+
+  ;; Simple accessors
+  (define cal-period-since cadr)
+  (define cal-period-before caddr)
+  (define cal-period-scomment cadddr)
+  (define cal-period-bcomment (compose cadddr cdr))
+
+  ;; Direct updater
+  (define (set-cal-period-scomment p c)
+    (list TAG-CAL-PERIOD
+	  (cal-period-since p)
+	  (cal-period-before p)
+	  c
+	  (cal-period-bcomment p)))
+
+  ;; Type predicate
+  (define (cal-period? p)
+    (and (pair? p)
+	 (eq? (car p)
+	      TAG-CAL-PERIOD)))
+
+  ;; Month subtype predicate
+  (define (cal-period-month? p)
+    (and (cal-period? p)
+	 (cal-month? (cal-period-since p))
+	 (cal-month? (cal-period-before p))))
+
+  ;; Day subtype predicate
+  (define (cal-period-day? p)
+    (and (cal-period? p)
+	 (cal-day? (cal-period-since p))
+	 (cal-day? (cal-period-before p))))
+
+  ;; Validation
+  (define (cal-period-valid? p)
+    (and (pair? p)
+	 (eq? (car p)
+	      TAG-CAL-PERIOD)
+	 (let ((since (cal-period-since p))
+	       (before (cal-period-before p)))
+	   (or (and (cal-month? since)
+		    (cal-month? before)
+		    (cal-month<=? since before))
+	       (and (cal-day? since)
+		    (cal-day? before)
+		    (cal-day<=? since before))))))
+
+  ;; Sorts period markers (be it start or end) chronologically and
+  ;; returns the sorted list.
+  (define (sort-period-markers l)
+    (sort l
+	  (lambda (a b)
+	    (cal-day/month<? (cadr a) (cadr b)))))
+
+  ;; Converts list of start/stop markers to list of pairs of months -
+  ;; periods. The markers are lists in the form (start/stop cal-month).
+  (define (period-markers->cal-periods l)
+    (let loop ((l (sort-period-markers l))
+	       (ps '())
+	       (cb #f))
+      (if (null? l)
+	  (list #t
+		(if cb
+		    (reverse (cons (make-cal-period (car cb) #f (cadr cb)) ps))
+		    (reverse ps))
+		""
+		-1)
+	  (let* ((marker (car l))
+		 (rmt (if cb 'stop 'start))
+		 (mtype (car marker))
+		 (month (cadr marker))
+		 (line-number (if (null? (cddr marker))
+				  #f
+				  (caddr marker)))
+		 (comment (if (and line-number
+				   (not (null? (cdddr marker))))
+			      (cadddr marker)
+			      #f)))
+	    (if (eq? mtype rmt)
+		(if cb
+		    (loop (cdr l)
+			  (cons (make-cal-period (car cb) month (cadr cb) comment) ps)
+			  #f)
+		    (loop (cdr l)
+			  ps
+			  (list month comment)))
+		(list #f
+		      (reverse ps)
+		      (sprintf "Invalid start/stop sequence marker ~A" marker)
+		      line-number))))))
+
+  ;; Returns duration of period in months. Start is included, end is
+  ;; not. The period contains the month just before the specified end.
+  (define (cal-period->duration p)
+    (let* ((b (cal-period-since p))
+	   (e (cal-period-before p))
+	   (e- (if e e (*current-month*))))
+      (cal-month-diff b e-)))
+
+  ;; Returns sum of periods lengths.
+  (define (cal-periods-duration l)
+    (apply + (map cal-period->duration l)))
+
+  ;; True if month belongs to given month period - start inclusive, end
+  ;; exclusive.
+  (define (cal-month-in-period? p . ml)
+    (let ((m (if (null? ml)
+		 (*current-month*)
+		 (cal-ensure-month (car ml))))
+	  (before (cal-ensure-month (cal-period-before p) #t))
+	  (since (cal-ensure-month (cal-period-since p))))
+      (and (or (not before)
+	       (cal-month<? m before))
+	   (not (cal-month<? m since)))))
+
+  ;; Returns true if given month is in at least one of the periods
+  ;; given. Defaults to current month.
+  (define (cal-month-in-periods? ps . ml)
+    (let ((m (if (null? ml)
+		 (*current-month*)
+		 (car ml))))
+      (let loop ((ps ps))
+	(if (null? ps)
+	    #f
+	    (if (cal-month-in-period? (car ps) m)
+		#t
+		(loop (cdr ps)))))))
+
+  ;; Returns true if given month is in at least one of the periods
+  ;; given. Defaults to current month.
+  (define (cal-month-find-period ps . ml)
+    (let ((m (if (null? ml)
+		 (*current-month*)
+		 (car ml))))
+      (let loop ((ps ps))
+	(if (null? ps)
+	    #f
+	    (if (cal-month-in-period? (car ps) m)
+		(car ps)
+		(loop (cdr ps)))))))
+
+  ;; Checks whether given day belongs to day or month period
+  (define (cal-day-in-period? p . dl)
+    (let ((d (if (null? dl)
+		 (*current-day*)
+		 (cal-ensure-day (car dl))))
+	  (before (cal-ensure-day (cal-period-before p)))
+	  (since (cal-ensure-day (cal-period-since p))))
+      (and (or (not before)
+	       (cal-day<? d before))
+	   (not (cal-day<? d since)))))
+
+  ;; Returns true if the day belongs to at least one period
+  (define (cal-day-in-periods? ps . dl)
+    (let ((d (if (null? dl)
+		 (*current-day*)
+		 (cal-ensure-day (car dl)))))
+      (let loop ((ps ps))
+	(if (null? ps)
+	    #f
+	    (if (cal-day-in-period? (car ps) d)
+		#t
+		(loop (cdr ps)))))))
+
+  ;; Returns string representing a month period with possibly open end.
+  (define (cal-period->string p)
+    (sprintf "~A..~A"
+	     (cal-day/month->string (cal-period-since p))
+	     (cal-day/month->string (cal-period-before p))))
+
+  ;; Returns a string representing a list of periods.
+  (define (cal-periods->string ps)
+    (string-intersperse
+     (map cal-period->string ps)
+     ", "))
+
+  ;; Finds a period the month matches and returns it. If no period
+  ;; matches, it returns #f.
+  (define (cal-periods-match ps .  ml)
+    (let ((m (if (null? ml) (*current-month*) (car ml))))
+      (let loop ((ps ps))
+	(if (null? ps)
+	    #f
+	    (if (cal-month-in-period? (car ps) m)
+		(car ps)
+		(loop (cdr ps)))))))
+
+  ;; Creates lookup table from definition source
+  (define (make-cal-period-lookup-table source)
+    (let loop ((lst source)
+	       (res '())
+	       (prev #f))
+      (if (null? lst)
+	  (reverse
+	   (cons (cons (make-cal-period (apply make-cal-month (car prev)) #f)
+		       (cdr prev))
+		 res))
+	  (loop (cdr lst)
+		(if prev
+		    (cons (cons (make-cal-period (apply make-cal-month (car prev))
+						 (apply make-cal-month (caar lst)))
+				(cdr prev))
+			  res)
+		    res)
+		(car lst)))))
+
+  ;; Looks up current month and returns associated definitions
+  (define (lookup-by-cal-period table)
+    (let loop ((lst table))
+      (if (null? lst)
+	  #f
+	  (if (cal-month-in-period? (caar lst))
+	      (cdar lst)
+	      (loop (cdr lst))))))
+
+  ;; Wrapper that accepts either day or month and returns testable month
+  (define (cal-ensure-month v . stop?s)
+    (if v
+	(if (cal-month? v)
+	    v
+	    (if (cal-day? v)
+		(apply cal-day->month v stop?s)
+		#f))
+	#f))
+
+  ;; Ensures day for checking the periods
+  (define (cal-ensure-day v)
+    (if v
+	(if (cal-day? v)
+	    v
+	    (if (cal-month? v)
+		(make-cal-day (cal-month-year v)
+			      (cal-month-month v)
+			      1)
+		#f))
+	#f))
+
+  ;; Performs self-tests of the period module.
+  (define (cal-period-tests!)
+    (run-tests
+     cal-period
+     (test-equal? sort-period-markers
+		  (sort-period-markers
+		   `((start ,(make-cal-month 2023 1))
+		     (stop ,(make-cal-month 2022 10))
+		     (start ,(make-cal-month 2022 3))))
 		  `((start ,(make-cal-month 2022 3))
 		    (stop ,(make-cal-month 2022 10))
-		    (start ,(make-cal-month 2023 1))
-		    (stop ,(make-cal-month 2023 4))))
-		 `(#t
-		   (,(make-cal-period (make-cal-month 2022 3)
-				      (make-cal-month 2022 10) #f #f)
-		    ,(make-cal-period (make-cal-month 2023 1)
-				      (make-cal-month 2023 4) #f #f))
-		   ""
-		   -1))
-    (test-equal? period-markers->cal-periods-open
-	         (period-markers->cal-periods
-		  `((start ,(make-cal-month 2022 3))
-		    (stop ,(make-cal-month 2022 10))
-		    (start ,(make-cal-month 2023 1))
-		    (stop ,(make-cal-month 2023 4))
-		    (start ,(make-cal-month 2023 5))))
-		 `(#t
-		   (,(make-cal-period (make-cal-month 2022 3)
-				      (make-cal-month 2022 10) #f #f)
-		    ,(make-cal-period (make-cal-month 2023 1)
-				      (make-cal-month 2023 4) #f #f)
-		    ,(make-cal-period (make-cal-month 2023 5) #f #f #f))
-		   ""
-		   -1))
-    (test-eq? cal-period->duration
-	      (cal-period->duration (make-cal-period (make-cal-month 2023 1)
-						     (make-cal-month 2023 4) #f #f))
-	      3)
-    (parameterize ((*current-month* (make-cal-month 2023 4)))
-      (test-eq? cal-period->duration
-		(cal-period->duration (make-cal-period (make-cal-month 2023 1) #f #f #f))
-		3))
-    (test-eq? cal-periods-duration
-	      (cal-periods-duration `(,(make-cal-period (make-cal-month 2022 3)
-							(make-cal-month 2022 10) #f #f)
-				      ,(make-cal-period (make-cal-month 2023 1)
-							(make-cal-month 2023 4) #f #f)))
-	      10)
-    (test-true cal-month-in-period?
-	       (cal-month-in-period? (make-cal-period (make-cal-month 2022 1)
-						      (make-cal-month 2022 4) #f #f)
-				     (make-cal-month 2022 3)))
-    (test-false cal-month-in-period?
+		    (start ,(make-cal-month 2023 1))))
+     (test-equal? period-markers->cal-periods
+	          (period-markers->cal-periods
+		   `((start ,(make-cal-month 2022 3))
+		     (stop ,(make-cal-month 2022 10))
+		     (start ,(make-cal-month 2023 1))
+		     (stop ,(make-cal-month 2023 4))))
+		  `(#t
+		    (,(make-cal-period (make-cal-month 2022 3)
+				       (make-cal-month 2022 10) #f #f)
+		     ,(make-cal-period (make-cal-month 2023 1)
+				       (make-cal-month 2023 4) #f #f))
+		    ""
+		    -1))
+     (test-equal? period-markers->cal-periods-open
+	          (period-markers->cal-periods
+		   `((start ,(make-cal-month 2022 3))
+		     (stop ,(make-cal-month 2022 10))
+		     (start ,(make-cal-month 2023 1))
+		     (stop ,(make-cal-month 2023 4))
+		     (start ,(make-cal-month 2023 5))))
+		  `(#t
+		    (,(make-cal-period (make-cal-month 2022 3)
+				       (make-cal-month 2022 10) #f #f)
+		     ,(make-cal-period (make-cal-month 2023 1)
+				       (make-cal-month 2023 4) #f #f)
+		     ,(make-cal-period (make-cal-month 2023 5) #f #f #f))
+		    ""
+		    -1))
+     (test-eq? cal-period->duration
+	       (cal-period->duration (make-cal-period (make-cal-month 2023 1)
+						      (make-cal-month 2023 4) #f #f))
+	       3)
+     (parameterize ((*current-month* (make-cal-month 2023 4)))
+       (test-eq? cal-period->duration
+		 (cal-period->duration (make-cal-period (make-cal-month 2023 1) #f #f #f))
+		 3))
+     (test-eq? cal-periods-duration
+	       (cal-periods-duration `(,(make-cal-period (make-cal-month 2022 3)
+							 (make-cal-month 2022 10) #f #f)
+				       ,(make-cal-period (make-cal-month 2023 1)
+							 (make-cal-month 2023 4) #f #f)))
+	       10)
+     (test-true cal-month-in-period?
 		(cal-month-in-period? (make-cal-period (make-cal-month 2022 1)
 						       (make-cal-month 2022 4) #f #f)
-				      (make-cal-month 2022 5)))
-    (test-true cal-month-in-periods?
-	       (cal-month-in-periods? `(,(make-cal-period (make-cal-month 2022 1)
-							  (make-cal-month 2022 4) #f #f)
-					,(make-cal-period (make-cal-month 2023 5)
-							  (make-cal-month 2023 10) #f #f))
 				      (make-cal-month 2022 3)))
-    (test-true cal-month-in-periods?
-	       (cal-month-in-periods? `(,(make-cal-period (make-cal-month 2022 1)
-							  (make-cal-month 2022 4) #f #f)
-					,(make-cal-period (make-cal-month 2023 5)
-							  (make-cal-month 2023 10) #f #f))
-				      (make-cal-month 2023 7)))
-    (test-false cal-month-in-periods?
+     (test-false cal-month-in-period?
+		 (cal-month-in-period? (make-cal-period (make-cal-month 2022 1)
+							(make-cal-month 2022 4) #f #f)
+				       (make-cal-month 2022 5)))
+     (test-true cal-month-in-periods?
 		(cal-month-in-periods? `(,(make-cal-period (make-cal-month 2022 1)
 							   (make-cal-month 2022 4) #f #f)
 					 ,(make-cal-period (make-cal-month 2023 5)
 							   (make-cal-month 2023 10) #f #f))
-				       (make-cal-month 2022 10)))
-    (test-equal? cal-period->string
-		 (cal-period->string (make-cal-period (make-cal-month 2022 1)
-						      (make-cal-month 2022 4) #f #f))
-		 "2022-01..2022-04")
-    (test-equal? cal-periods->string
-	         (cal-periods->string `(,(make-cal-period (make-cal-month 2022 1)
-							  (make-cal-month 2022 4) #f #f)
-					,(make-cal-period (make-cal-month 2022 12)
-							  (make-cal-month 2023 2) #f #f)))
-		 "2022-01..2022-04, 2022-12..2023-02")
-    (test-false cal-periods-match
-		(cal-periods-match `(,(make-cal-period (make-cal-month 2022 1)
-						       (make-cal-month 2022 4) #f #f)
-				     ,(make-cal-period (make-cal-month 2022 12)
-						       (make-cal-month 2023 2) #f #f))
-				   (make-cal-month 2022 5)))
-    (test-equal? cal-periods-match
+				       (make-cal-month 2022 3)))
+     (test-true cal-month-in-periods?
+		(cal-month-in-periods? `(,(make-cal-period (make-cal-month 2022 1)
+							   (make-cal-month 2022 4) #f #f)
+					 ,(make-cal-period (make-cal-month 2023 5)
+							   (make-cal-month 2023 10) #f #f))
+				       (make-cal-month 2023 7)))
+     (test-false cal-month-in-periods?
+		 (cal-month-in-periods? `(,(make-cal-period (make-cal-month 2022 1)
+							    (make-cal-month 2022 4) #f #f)
+					  ,(make-cal-period (make-cal-month 2023 5)
+							    (make-cal-month 2023 10) #f #f))
+					(make-cal-month 2022 10)))
+     (test-equal? cal-period->string
+		  (cal-period->string (make-cal-period (make-cal-month 2022 1)
+						       (make-cal-month 2022 4) #f #f))
+		  "2022-01..2022-04")
+     (test-equal? cal-periods->string
+	          (cal-periods->string `(,(make-cal-period (make-cal-month 2022 1)
+							   (make-cal-month 2022 4) #f #f)
+					 ,(make-cal-period (make-cal-month 2022 12)
+							   (make-cal-month 2023 2) #f #f)))
+		  "2022-01..2022-04, 2022-12..2023-02")
+     (test-false cal-periods-match
 		 (cal-periods-match `(,(make-cal-period (make-cal-month 2022 1)
 							(make-cal-month 2022 4) #f #f)
 				      ,(make-cal-period (make-cal-month 2022 12)
 							(make-cal-month 2023 2) #f #f))
-				    (make-cal-month 2022 2))
-		 (make-cal-period (make-cal-month 2022 1)
-				  (make-cal-month 2022 4) #f #f))
-    ))
+				    (make-cal-month 2022 5)))
+     (test-equal? cal-periods-match
+		  (cal-periods-match `(,(make-cal-period (make-cal-month 2022 1)
+							 (make-cal-month 2022 4) #f #f)
+				       ,(make-cal-period (make-cal-month 2022 12)
+							 (make-cal-month 2023 2) #f #f))
+				     (make-cal-month 2022 2))
+		  (make-cal-period (make-cal-month 2022 1)
+				   (make-cal-month 2022 4) #f #f))
+     ))
 
- )
+  )
diff --git a/src/mbase-query.scm b/src/mbase-query.scm
index af7ed30..df560af 100644
--- a/src/mbase-query.scm
+++ b/src/mbase-query.scm
@@ -47,6 +47,13 @@
   (define (members-base-oldest-month mb)
     (make-cal-month 2015 1))
 
+  (define (members-average-age mrs)
+    (let* ((ages (map brmember-age mrs))
+	   (valid (filter (lambda (x) x) ages))
+	   (num (length valid))
+	   (sum (foldl + 0 valid)))
+      (exact->inexact (/ sum num))))
+
   ;; Returns dictionary with statistics about the members base.
   (define (mbase-info mb-arg)
     (let* ((members (find-members-by-predicate mb-arg brmember-usable?))
@@ -81,10 +88,10 @@
 				   (map (lambda (v)
 					  (min 0 v))
 					mbals))))
-	   ;; debts of fees
-	   ;; add average age of active members
+	   (di13 (ldict-set di12 'age
+			    (members-average-age active-members)))
 	   )
-      di12))
+      di13))
 
   ;; Returns a list two lists: keys, data.
   ;; Each data record contains values for all keys.
@@ -93,6 +100,7 @@
 	   '(month
 	     total active suspended students destroyed invalid
 	     expected balance advance debt
+	     age
 	     )))
       (let mloop ((data '())
 		  (month (members-base-oldest-month mb)))