Measuring the progress of KRs as a percentage.

I'm creating a sales objective with 4 KRs. I choose "number" as the metric because the currency I need (SAR) isn't available (thank you very much, Microsoft!). Anyway, the mode of update is automatic through Excel Online. The problem is, the progress of each KR is calculated as an achievement out of a total number without specifying the percentage of that achievement! 

How can I get it to also display the percentage?