How to calculate percentage in a pivot table (from a tally)?

Hi,

I have created the following pivot table. (Please see the excel file attached here).

I have used the pivot table to display Total Wins and Losses.
However, it seems I am unable to calculate "Win %" in the pivot table. I want to ONLY show the percentage of Wins (vs losses).

My original data is included in the attached file. It uses a 'tally' to record Wins and Losses.
Simply: If there is a '1' in the Win Column, that means a win. If there is a '0' it means a Loss.

Could someone kindly help me do this?

My EXCEL file: cumul raw separates.xlsx

Illustration of my data: http://imgur.com/mzHMGdz

To be clear, the pivot table shows "Character" and "Opponent".
So here it shows that "Fox vs 'Opponent:' C.Falcon" is 2 wins, and 0 losses. Instead of showing this, it should show his % win. So it should say 100%. Because Fox beat C.Falcon 2-0.

Ideally, I would like to add this function in the pivot table (if possible).

Hope you can understand!