epa results after 2 years

With the epa results being tested on new cars I started to wonder with the prius seeming get better with 15,000 miles or so what would it official end up being then. I got my prius in the winter of 08 and the gas mileage went up steadily with the temp. that summer I had one tank the whole summer at 60. This summer I had almost every tank near 58 and 60. It could be learning how to drive it to do that but I think there is a certain break in period in the car. Not like this will change anyone's mind but would be an interesting fact to know.