Cowen built a lot on the median income in The Great Stagnation; reading it, there was not a whisper about demographics, though Cowen is a pretty honest author usually (and in fact was the one who publicized this one!).
Drat, I hat-tipped Cowen instead of David Henderson of Econlog, in an example of the Matthew Effect. http://en.wikipedia.org/wiki/Matthew_effect_(sociology)#Sociology_of_science
ETA: The table linked by Landsburg has been called into serious question by Evan Soltas [H.T. CronoDAS]. I edited the post to leave only the table to provide context for the comment discussion of its status.
Economist Steve Landsburg has a post [H.T. David Henderson] about the supposed stagnation of median wages in the United States in recent decades. In the linked table median wages have risen for: