In its annual U.S. living-standards snapshot, the bureau said 36.5 million people, or 12.3 of the U.S. population, lived in poverty last year.

This is 0.3 percent less than 2005's 12.6 percent figure, which the bureau said was not a statistically significant difference.

The number of people without health insurance coverage rose to 47 million, or 15.8 percent of the population, from 44.8 million, or 15.3 percent, in 2005, the bureau said.

The median household income -- with half making more and half making less -- was $48,200, a slight increase from 2005, but short of 1999's $49,163 peak.

Asian households had the highest median income at $64,200, followed by non-Hispanic white ($52,400), Hispanic ($37,800) and black ($32,000) households, the bureau said.

The best-off fifth of U.S. households claimed 50.5 percent of pre-tax income in 2006 while the bottom three-fifths shared 26.5 percent of pre-tax income.

In 1986, the top fifth got 46.2 percent of the income and the bottom three-fifths got 29.5 percent.