I got a solution by creating a table of dates and their associated
fiscal years. For instance in A1 I have 7/1/2005; in B1I have
7/31/2006; in C1 I have 2006. Row 2 is for fiscal 2007, row 3 for 2008
and so on thru row 6 (fiscal 2011).

In cell B9 I have the date 12/31/2005; in c9 I have the formula
=SUMPRODUCT(--(B9=$A$1:$A$6),--(B9<=$B$1:$B$6),$C$1:$C$6)