From: "Frank Kabel"

Hi
in B1 enter the following array formula (entered with CTRL+SHIFT+ENTER)
formula:

=IF(A2<"","",COUNT(OFFSET($A2,0,0,-(SUM(ROW($A2))-MAX(IF($A$1:$A1="",ROW
($A$1:$A1),0))))))

and copy this down

Beautiful. Thanks, so much.