I have made a spreadsheet to keep attendance based on percentages. I want to
be able to insert a formula in the last column to calculate a running average
total. Example, at the end of March they have 100%, but in April they only
have 50% attendance, so the yearly would be 87.5%.

It can't be that difficult, but I can't figure out how to do it. Plus, I
don't want to change the formula each month.

THANKS
--
Tammy