One of the most important stories in the U.S. economy these days is the rise of extreme inequality.

Over the past 30 years, a larger and larger portion of America's income growth has gone to those in the top 10% of incomes, and especially those in the top 1%. This is a major change from the prior 60 years, in which the top 10% and the bottom 90% shared in the income gains.

A stark and startling example of this trend is the fact that, adjusted for inflation, "average hourly earnings" in this country have not increased in 50 years.