Please forget my previous post.

Use the following array formula instead:

=INDEX(D213,MATCH(1,((A2:A13>=DATE(YEAR(E2),MONT H(E2),1))*(B2:B13<=DATE(YEAR(E2),MONTH(E2)+1,0))), 0))

(Must be entered by holding down Ctrl and Shift before pressing Enter).


(Anyone who knows how to avoid the Big Grin icon when one enters for example D2 colon D13?)