Need formula to sum every 12 cells to get yearly amounts

I need some help writing a formula to sum every 12 cells in a column to get yearly amounts. i.e. a4:a15 would sum to year 1 & a16:a27 would sum to year 2.

Please let me know how to adjust my formula. Workbook attached. Thanks!

Put this in G4:

=SUMIFS(B:B,A:A,">"&(F4-1)*12,A:A,"<="&F4*12)

then copy down to G33.

Hope this helps.

Pete

awesome. thanks pete