Hi

=SUMPRODUCT(--(A1:A1000),--(B1:B1000) ) for 2006
=SUMPRODUCT(--(A1:A1000),--(C1:C1000)) for 2007
=SUMPRODUCT(--(A1:A1000),--(B1:B1000),--(C1:C1000)) for both years
--
Regards
Roger Govier

"blswes" wrote in message
...
Trying to count how many customers there were in 2006 only vs. 2007 only
vs.
2006 & 2007.

Data's set up with Customer ID and Year columns, so if a customer is part
of
both 2006 and 2007, then there would be two separate rows (one for each
year).

Any suggestions?