We are using excel 2000 to report our daily and monthly production numbers.
We have one file for each month with one work sheet for each day and monthly
sheet. In monthly sheet, we want add a column it should show last 12 months
total including current month. Is it possible? If so, what is the easiest way
to do.

Any help will be appreciated.

File name for each month ex: DR01_month 2005