 One way of quantifying the polarization of the economy is to compare the fraction of those with incomes that are close to the middle—for example, a range that goes from 50 percent greater than the median to 50 percent less than the median—has fallen since 1970 from just over 50 percent to just over 42 percent.Similarly, the U.S. and the E.U.have shown almost identical trends in the share of employment rise by the high and low skill jobs, and a loss by the middle skill jobs, between 1993 and 2006.