so sorry for the delay in my reply !!
I was unable to see a bunch of posts until now for some reason - but this is all fixed now!
To get your percentage saved , you can do this one of 2 ways ( depending if you want to know the
percentage in coupon savings, or the percentage from the regular price + coupons.)
so say you had $10 total saved from the sale prices + $15 in coupons redeemed, and you total receipt paid was
$50 then you would have saved 50%.
if only using the coupons percentage - you would have saved approx 31%.(rounded)