Calculate Percentage based on Running Sum display

I'm displaying a running sum for minority hires and overall hires from month to month. I want to calculate the % of minorities to hires for each month based on the running sum but can't seem to get there.

Here is some example data. Example: February, without running sum it would be 0%. With running sum it should be 37.5% but I'm still getting 0. Any ideas on a formula for this? Appreciate any feedback :) Attached is my xml as well.