Crystal Reports Cross-Tab Amount and percent Column

Message

   I am new to crystal reports and have done a training class but not much was covered on cross-tab reports.
I am trying to desgin a cross-tab report that will display both the dollar sum amt and percent of for each category.  

               USA Region
               Main Office Total            Specailty Office Total

Total       4150                                300
LOS         1000      24.09%             150      50%
EOD         3000      72.28%             100      33.33%
MOP           150        3.61%               50     16.67%

How would I go about adding the percent calculation to each column?

Thanks.