Consider a couple with one child making $50,500 (2013 dollars) in 1989 before considering capital gains (this is roughly the mean income of the middle quintile). . . In 2007, the couple at the same point in the distribution would make $61,000 before capital gains. This is a 20% increase. ...
Now consider a high-income couple with one child making $200,000 (in 2013) dollars in 1989 (this is roughly the mean income of the top 5%) excluding capital gains . . . In 2007 a couple at the same point in the distribution would make $230,000 ....
Something seems odd here: the earnings of their middle couple grew by 20% ($50,500 to $61,000), while the earnings of the top 5% couple grew by 15% (200,000 to 230,000). So even before all of the adjustments including in-kind income, accrued capital gains, etc., the middle was gaining on the top.The original source of their data was the Current Population Survey. I went to the CPS website and found a table called "Mean Household Income Received by Each Fifth and Top Five Percent, 1967-2011." According to that table, the mean income of households in the third fifth was $50,657 in 1989 and $54,202 in 2007 (both in 2011 dollars), an increase of 7%. The mean income of households in the top 5% was $242,007 in 1989 and $311,524 in 2007, for an increase of 29%.