Mean vs. Median

Matt Yglesias makes a good point, while discussing an article by Fred Barnes:

Although mean income (aggregate income divided by number of households) has risen over the past few years, median income (if you line up American households by income, the income of the household in the exact middle) has gone down.

This would indicate that the increase in mean income has come entirely from an increase of the income of people in the top half.

I don't agree, of course, with the liberal solution (tax those dirty rich people) to the problem (if it is a problem). But this is an important thing to realize. And it is important to call Mr. Barnes on his, if not entirely deceptive, then at least not complete statistical analysis.

A blogger calling himself RSA graphed this.

What would actually be very helpful would be graphs of the trends in income at different percentile points over the last 25 years or so; i.e. how are people at the 25th percentile doing, the 50th percentile (actually, that is on the graph; the 50th percentile is the median), the 75th percentile, etc. This would show more exactly whose income is increasing and whose is decreasing.

Anyone know of such a graph?

That is all.