I live in the South Califonia desert and my car sits out on the road all the time. It is a 2001 and doesn't show any signs of paint wear. The car was in a garage for six months while I was deployed a couple years ago, but other than that, it is outside uncovered. Most of my driving is under 40MPH to and from work. I only have 25K miles also. If you drive at highway speeds, maybe the blowing sand is sand blasting it?
Under my hood, I have paint flaking off on the top of the side panels, about the size of a thumb print each. I just recently fixed a coolant leak from the thermo housing so am not sure if the coolant caused this. The leak had been going for a couple months.
Color of my focus is malibu blue.