Pivot table field B as a % of field A

[Erin Searfoss]

I'd like to create a pivot table like the following in Excel 2003. Is this
possible?

Column Data--------------------------------
Weeks Count of A Sum of B Sum of B as
% of Ct of A
1 429 9 2%
2 315 38 12%
3 165 31 19%
4 146 13 9%