I calculate mpg at every fuel fill. I get consistently well over 17mpg with my well maintained 560SL. My driving is mainly rural with a little city driving maybe twice per week. I don't dog it. The car is a daily driver on which I put 12420 miles in 2008. Mileage in excess of 18mpg is common and I have gotten over 20mpg on a non-stop 220 mile trip.