Hello I am trying to make a pivot table with a custom "Grand total"
calculation.

For example I need to calculated compound interest in the grand total
field. Is this possible?

Suppose 10% return every month (Jan-Dec)compounded monthly.

jan feb mar ... TOTAL
2001 10% 10% 10%... 313.8%
2002 10% 10% 10%... 313.8%
2003 10% 10% 10%... 313.8&
-------------------------------


TOTAL = exp(sum(log(1+n))


ANY HELP IS APPRECAITED!!!!