Median per capita income has basically been flat since 2000, adjusted for inflation. The typical American family makes slightly less than a typical family did 15 years ago. And while many goods have become cheaper or better, the price of three of the biggest middle-class expenditures ”“ housing, college and health care ”“ have gone up much faster than the rate of inflation.
Equally important, Mr. Hirschl found a high degree of income volatility among most Americans in the four decades between 1969 and 2011. At some point in their working lives, a full 70 percent earned enough to put them in the top fifth of earners, and as many as 30 percent reached the equivalent of $200,000 in 2009 dollars, or roughly the top 4 percent.
Similarly, nearly 80 percent will at least temporarily plunge into a red zone, where their income drops near or below the poverty line, or they are compelled to gain access to a social safety net program like food stamps or collect unemployment insurance. More than half of Americans ages 25 to 60 will experience at least one year hovering around the poverty line.
Read it all (my emphasis).