The broad facts of income inequality over the past six decades are easily summarized:
- The years from the end of World War II into the 1970s were ones of substantial economic growth and broadly shared prosperity.
- Incomes grew rapidly and at roughly the same rate up and down the income ladder, roughly doubling in inflation-adjusted terms between the late 1940s and early 1970s.
- The income gap between those high up the income ladder and those on the middle and lower rungs — while substantial — did not change much during this period.
- Beginning in the 1970s, economic growth slowed and the income gap widened.
- Income growth for households in the middle and lower parts of the distribution slowed sharply, while incomes at the top continued to grow strongly.
- The concentration of income at the very top of the distribution rose to levels last seen more than 80 years ago (during the "Roaring Twenties").
- Wealth (the value of a household's property and financial assets net of the value of its debts) is much more highly concentrated than income, although the wealth data do not show a dramatic increase in concentration at the very top the way the income data do. ...