I see about 18 and change running straight highway...That's being fairly 'good' but w/ a few quick runs up to 110-120 just to keep things interesting.
I've checked it on about 10 tanks driving back and forth from FL to GA and GA to VA.
Don't bother keeping track of my around town mileage..I don't really want to know, nor do I drive it around town much..defeats the purpose of this car (IMHO).
Hope that helps
Jonathan