I have a workbook (using Excel 2002) that takes the data on the worksheet
"AllDealers" (960 rows x 112 cols) and spreads it to regional sheets (16 in
all). This process (on my machine usually takes about 4-6 minutes.

Then I added another 91 columns with historical data and now the same
calculation takes approximately 1 hour and 15 minutes. What a difference?
Can anyone explain why?

If I were to put this historical data in another worksheet, how can I tie
the two sheet together?

Any help will be appreciated.