Paul Krugman makes the important point that the substantial gains in income for the richest Americans has been concentrated in a very small group. It’s not the top 10% or the top 5% or even the top 1% that has prospered the most — it’s the top tenth of 1% and the top hundredth of 1% who have substantially increased their share of the national income:
Of the gains made by the top 10 percent [since 1979], almost none went to the 90-95 group; in fact, the great bulk went to the top 1 percent. The bulk of the gains of the top 1, in turn, went to the top 0.1; and the bulk of those gains went to the top 0.01. We really are talking about the flourishing of a tiny elite.
In other words, income has only increased for the top 5.0% since 1979, and more than half of that increase went to the top 0.1%. It’s as if the bottom 95.0% of Americans haven’t received a raise in 30 years.