In the following table in Excel; Colum A is the MMMM-YY format for dates and
column B is my data. How do I get a rolling 6 month total, rolling 12 month,
and rolling 18 month total?

January-02 2
February-03 15
March-03 0
April-03 0
May-03 0
June-03 5
July-03 6
August-03 4
September-03 0
October-03 0
November-03 2
December-03 0
January-04 0
February-04 0
March-04 0
April-04 4
May-04 5
June-04 2
July-04 0
August-04 20
September-04 10
October-04 3
November-04 5
December-04 0
January-05 0
February-05 0
March-05 0
April-05 10
May-05 0
June-05 0

I have used the following in the cell to come up with a yearly total

=SUMIF(A1:A100,"=" &DATE(YEAR(TODAY())-1,MONTH(TODAY()),1),B1:B100)

but am trying to get a 6 month and 18 month total. Also I am looking for
data between Jan 04 and Dec 04 only.

Any help would be appreciated.