Ironically enough, I've an AT 2010 with 27k miles on it, and I'm getting an avg of 21.4mgp city and 24mpg hwy right now, according to the cpu...
I've been making sure to not "floor it" while driving, for the most part.. also, i've been keeping my fuel consumption gauge between the 20 - 40 mark as best as i can... I mean, no need to rush if you don't have to...
One last note - i find the most fuel efficient speed to be 55mph IMO...