I have a list of data by date of power production. What I want to know is
how much power was generated in December 2009, January 2010, etc. The data in
a sheet with the dates in column A and power production in column B. I have
another tab with the months in the rows and the years on the columns.

I am sure there is a way to do this with sumproduct, but i am not sure how to.

Thanks in advance.