Interesting. I'm a life scientist, and I'm definitely doing better than my parents were at my age. My fiancee also doesn't quite fit the mold. She's a designer, but quite a successful one. Not sure how she compares with her parents' income at her age, but I imagine it's ahead. I'm not sure designers should be lumped with artists and musicians, however, because designers get industry jobs, whereas the others don't.
Also, who knew that police officers did so well? That makes me and my tax dollars angry :/