Impressed with my wife's '03 Camry mpg

[cs1992]

My wife has an '03 Camry 4 cylinder automatic with ~38k on the odometer. This car continues to impress me with the mpg it achieves. Yesterday's filling up indicated 31.4 mpg...mostly city driving. The highest I have measured is 35.4...all highway.My Vibe with 5k miles gets the same mileage. This surprises me because the Camry is much larger, has a bigger engine and weighs more. Although, the mpg on the Camry did not begin to increase until it had about 15k on it. Before this, she was averaging ~28mpg.