I have a work sheet with more than 300 customers in rows with sales volumes
posted in
month wise for the last 3 years (Apr, May, June etc.,).

I can attach the sheet for your ready ref.

I want a comprehensive caliculation of the data on current vs historical
(2006-07 vs 2005-06)
1. Percentage growth
2.Market Share
3.Sales in trading area.
4.Any advanced help in analysing the sales of the dealer in that trading area.