Percentage Calculation

I am a Safety representative and on a monthly basis I have to check for seat belt usage. I can not, for the life of me, figure this out.

I have attached an example. In the example out of 22 vehicles there were 2 individuals not wearing seat belts. So cell J4 should be 91%

I can calculate % not wearing with [=sum(D4:E4,H4:I4)/SUM(B4:I4)]
but I want to show % wearing.

Thanks