Pivot table - calculating percentage on grand total

Hi,

I have a Pivot table that calculates the profit (grand total) on various orders. Now I would like to include a profit percentage (profit / revenue = profit in percentage).
I would like to include it in the Pivot table in order to be able to use this table as basis for creating a new Pivot table (on another sheet - an overview sheet) which shows the top 5 orders based on profit percentage.
How to do this?

I have attached a small example.

Thanks for any help you can provide.