Calculating percentages skipping few items in a report

Hello Gurus,

In my query Under rows I have a structure with following items:

trade sales

net sales

net income

op income

In my columns I have entities america, china, europe

My report is as below:

America China Europe

trade sales 40 35 45

net sales 40 37 50

net income 10 8 15

op income 12 10 12

My requirement is as below:

America China Europe

trade sales 40 35 45

net sales 40 100% 37 100% 50 100%

net income 10 25% 8 21.6% 15 30%

op income 12 30% 10 27% 12 24%

How do I calculate these percentages?? Please any idea to this problem would be of great help.

Thanks,

Nikki