U.S. households are frequently divided by the Department of Commerce into equal “fifths” in terms of mean (average) income. This division helps track the movement of households within the income classes, i.e. Poverty, Lower Income, Middle Income, Upper Income, and High Income.
Looking at the mean household income from 2002 to 2012, the slow growth of the lower 80% of households is apparent, while the top 20% is growing at a steady rate with the top 5 percent adding to the widening gap between the middle class and high income households.
Both the Highest Fifth and Top 5 percent of households grew 27% from 2002. The Top 5 percent jumped from a mean income of $251,000 in 2002 to $318,052 in 2012, while the highest 20% overall increased from $143,743 to $181,905.
In 2012, the mean household income for the Fourth Fifth quintile was $82,098 and $51,179 for the Third Fifth – both increasing an average of 21% from 2002. The lowest 2/5th of households increased their mean incomes by an average of 16%.