I want to create a formula in cell B13 that will add up cells B1 thru B12 and
give me an average in B13. However, B1 thru B12 represent each month and I
want a running monthly average figured in B13 as I enter each month. So... I
want to enter January Figure in B1, February Figure in B2 and have the
Average in B13. Then I want to add March Figure in B3 and have the average
of the first three in B13 and so on and so on so I can compare Monthly
Averages this year with a total monthly average from Last year in column B14.
I have no idea how to do this. Any help is appreciated!

Thanks to all,
--
Sam