US income inequality: caused by financiers and tech entrepreneurs

Income inequality in the United States is at historic highs, after significant increases in the last decade. For example, in 2003-2004 the average income of the top 1 percent of the population increased by 17 percent while that of the remaining 99 percent increased by only 3 percent in real terms.

It is important to understand this phenomenon in more detail: is there a widening nationwide gap between the rich and all others? Data on incomes by county covering the mid to late 1990's, from the government Bureau of Economic Analysis, shows an interesting geographical pattern. Most of the gains enjoyed by the top 1% came from a small number of counties. In particular, income increases at the top end in tech hotbeds Seattle and Silicon Valley, and finance capital New York City, account for almost all of the aggregate nationwide increase. If four counties in those regions are removed, there is almost no increase in inequality during that period.

So, the good news is there isn't a national phenomenon at work here (and, perhaps, Bush is not to blame -- at least, if tax cuts were the cause I would expect the effect to be more uniform geographically; future data will tell). Let me be the first to welcome our financier and tech entrepreneur overlords! :-)