That’s a lot, it’s too late to work out the numbers accurately but I just did Winnipeg to Iowa and back then out to Toronto and back over 9 days which is rouhgly 450 gallons of fuel, I left with full def and at the end of the trip I put just over 15 gallons in. So you’re looking at 3.5 gallons of DEF per 100 gallons of fuel. That’s a '15 Cascadia Evo DD13, no idling when not driving.