Rick -

I have not looked at your data, but if you have monthly seasonality with
linear trend, you could use one of the three methods described in the "Time
Series Seasonality" chapter of my book "Data Analysis Using Microsoft Excel:
Updated for Office XP." One approach is linear time trend regression with
indicator (zero or one) variables for seasonality; another is autoregression
with both lag 1 to model trend and lag 12 to model seasonality. The methods
are a bit too much to explain in an email message, but you might be able to
find some online explanations using google or google groups.

- Mike
www.mikemiddleton.com

"Rick Pusateri"
wrote in message
news:Rick.Pusateri.241zoy_1141321504.4461@excelfor um-nospam.com...

Thanks, Gary - appreciate your response. The problem I see is that there
is seasonality to the numbers, and the % subset is growing overall. How
does your equation factor that piece in? Thanks!

Rick