The difference between EPA numbers (which, by law, are the only numbers they are allowed to use) and what Real Drivers get in the Real World is such an old issue that one of the net's oldest acronyms is based on it:
YMMV Your Mileage May Vary.
Actually anyone who is not driving on an EPA dyno in perfect weather with raw eggs between their feet and the pedals will get worse mileage.
Next year it will get better... EPA will be giving out more realistic numbers.
Explained: 2008 EPA Fuel Economy Ratings