History: United States Of America, 1940

According to the United States Census Bureau, the pretax median household income in 2007 was $49,777. The median ranged from $65,469 among Asian American households to $32,584 among African American households. Using purchasing power parity exchange rates, the overall median is similar to the most affluent cluster of developed nations. After declining sharply during the middle of the 20th century, poverty rates have plateaued since the early 1970s, with 11–15% of Americans below the poverty line every year, and 58.5% spending at least one year in poverty between the ages of 25 and 75. In 2009, 43.6 million Americans lived in poverty.
The U.S. welfare state is one of the least extensive in the developed world, reducing both relative poverty and absolute poverty by considerably less than the mean for rich nations, though combined private and public social expenditures per capita are higher than in any of the Nordic countries. While the American welfare state does well in reducing poverty among the elderly, the young receive relatively little assistance. A 2007 UNICEF study of children's well-being in twenty-one industrialized nations ranked the United States next to last.
Despite strong increases in productivity, low unemployment, and low inflation, income gains since 1980 have been slower than in previous decades, less widely shared, and accompanied by increased economic insecurity. Between 1947 and 1979, real median income rose by over 80% for all classes, with the incomes of poor Americans rising faster than those of the rich. Median household income has increased for all classes since 1980, largely owing to more dual-earner households, the closing of the gender gap, and longer work hours, but growth has been slower and strongly tilted toward the very top. Consequently, the share of income of the top 1%—21.8% of total reported income in 2005—has more than doubled since 1980, leaving the United States with the greatest income inequality among developed nations. The top 1% pays 27.6% of all federal taxes; the top 10% pays 54.7%. Wealth, like income, is highly concentrated: The richest 10% of the adult population possesses 69.8% of the country's household wealth, the second-highest share among developed nations. The top 1% possesses 33.4% of net wealth.