Brad DeLong is surprised by this chart:
I suspect this is surprising only to people like Brad and me (and most of our readers): that is, college educated, white collar workers who make pretty good incomes and work in jobs where continual lifetime advancement is the norm. But that’s definitely not the norm for the vast majority of the country. If you work as a truck driver or a waitress or an accounts payable clerk, then by the time you’re 40 you’ve peaked out. Your job pays what it pays, and once you’ve accumulated a few years of experience you make as much as you’re ever going to make. It’s a different world from the one lived in by the upper middle class, and unfortunately, it’s an increasingly foreign one to a lot of us.