Starting with the 2008 models, the EPA changed the way it calculated the MPG of all cars and trucks. They now have two people in each vehicle and do actual road tests in real driving conditions. That's why all 08 models took a hit on their ratings.
But, don't go by the highway MPG. That's only under the most ideal situations ... dry, open highway and c/c set at 65. If you can't use the c/c, it drops from 2 to 5 MPG, depending on traffic. And any time you drive on the street, it drops further.
Even though the EPA ratings are more realistic, the best way to decipher what your overall MPG will be (both city and highway driving) is to take the City MPG and add 3 if you live in a small or medium size town. Or add 1 if you live in a large town or big city. Stop and go traffic kills your mileage. Do that and you'll get the most accurate MPG for the car you're considering.
Me. New car sales manager for over 30 years.