I have a tally table based on certain criteria from a list of data.
The example is below

no. buys bought on time no. buys bought correct total no buys
Sam 4 4 4
Dave 19 14 22
Fred 10 9 12
Totals 33 27 38

I need to provide a percent against each of the values, but would like to weight these as some people have had more buys than others.
How can I do this?

Thanks.