MasterCard Advisors estimates retail gasoline demand based on aggregate sales activity in the MasterCard payments system coupled with estimates for all other payment forms.

It looks like this refers to all gasoline purchased, not just credit cards. I don't know how good the data is, but it does seem clear Mastercard is presenting it that way.

I know, but I question whether their model is accurate, given the recent changes I mentioned.

I'm just watching from the cheap seats, but wouldn't a more accurate measure be gasoline production (plus imports), averaged over months, etc.? I would think that virtually all such gasoline ends up being used in vehicles...

Is that showing a downward trend?