Account Schedule - Statistics Column

song

Does anyone have the old manual for the account schedule where there is a field for the base amount so that there will be a statistics column. Right now, percentage can be computed in the Account Schedule but the basis is column to column, what i need is for account schedule to reflect the percentage computed from the rows in a separate column.

Example:

Sales Per Area Amount Sales Per Area to Total
Sales-EU $10 10%
Sales-Asia $20 20%
Sales-US $70 70%
Total Sales $100 100%

Please help.