Class in the US... the fourth conclusion

4The share of U.S. aggregate household income held by middle-income households has plunged, from 62% in 1970 to 43% in 2014. Meanwhile, the share held by upper-income households increased from 29% to 49%. This shift is driven both by the growing size of the upper-income tier and more rapid gains in income at the top.

There is also a growing disparity in the median wealth (assets minus debts) of these income tiers. Upper-income families, who had three times as much wealth as middle-income families in 1983, more than doubled the wealth gap to seven times as much in 2013.

http://www.pewresearch.org/fact-tank/2015/12/10/5-takeaways-about-the-american-middle-class/