I am trying to calculate an annualized rolling sum for data as follows:

ColumA Column B
10/01/97 5
10/12/97 6
12/5/97 3
1/5/98 2
1/15/98 6
6/15/98 9
8/12/98 7
etc

I want to be able to calculate on each date the sum of column B for the past
year.