I average 24mpg mostly city w/some highway. I drive fairly conservatively (keep it under 3k) most of the time, but I still beat on it now and then.
On my last tank of gas I tired 100% grandma driving by keeping it under 3k and under 70mph on the freeway. The car achieved the exact same gas mileage as it does when I beat the piss out of it once or twice on my way to/from work. No matter what, I can't seem to get better than 24mpg.