Creating a running percentage chart

Hi All

I have a dataset, which is broken up into 4 populations (which is my series). I am trying to create a chart (or table) that shows the percentage of each population that had made their first purchase by a given day after signing up as a member (ie- % that bought for the first time by day one, then cumulative percentage that had bought by day 2, day 3) until eventually at some point each population would be showing 100%.

I'm trying to manipulate a Running Total Line chart to make it a running percentage, but I'm having no luck. Can anyone suggest another way to approach this?

My data is set out as follows:

Any guidance would be appreciated.

Thanks