We use litres here, but for my post I converted to US gallons. Sounds like dieselmbfan did that same.. What speed were you driving and was it only highway? I think the best I got last summer was driving through Saskatchewan heading east at an average speed of about 130 km/h. Of course it is slightly down hill all the way to Ontario
.. and I believe that part of the trip averaged to about 15.5 L/100km or 37 mpg. I imagine if I had been driving slower it would be slightly better, but the car just loved going 130-140 and the drive was so boring!!
Not sure if I've had any better.
I don't know if we use the imperial gallon or not.. I don't come across much stuff that's in gallons, if ever.