Wow. You're getting awesome mileage compared to mine. Rural driving at 60 MPH yields 24-26 MPG. I live in the suburbs, and regularly go downtown, and then my mileage is 21-22. I don't drive hard at all----I don't impede traffic, but I don't out accelerate anyone at stoplights, either. I used to get 30 MPG all day long in my 07 WRX. Needless to say, I'm quite disappointed.
2009 Aveo5 LT Automatic - 17k miles.
I just had the O2 sensors both replaced under warranty, we'll see if that helps my mileage at all. I'm not very optimistic, tho.