Jeffrey S. Passel

The 2010 Census counted 50.5 million Hispanics in the United States, making up 16.3% of the total population. The nation's Latino population, which was 35.3 million in 2000, grew 43% over the decade.

The number of Hispanics counted in the 2010 Census was nearly 1 million more than expected, based on the most recent Census Bureau population estimates.

The number of Hispanics counted in the 2010 Census has been larger than expected in most states for which the Census Bureau has released detailed population totals so far, with the widest gaps in states with relatively small Hispanic populations.

The annual inflow of unauthorized immigrants to the U.S. was nearly two-thirds smaller in the March 2007 to March 2009 period than it had been from March 2000 to March 2005.

An estimated 340,000 of the 4.3 million babies born in the United States in 2008 were the offspring of unauthorized immigrants, according to a new analysis of Census Bureau data.

This dramatic increase has been driven in part by the weakening of longstanding cultural taboos against intermarriage and in part by a large, multi-decade wave of immigrants from Latin America and Asia.

The flow of immigrants from Mexico to the United States has declined sharply since mid-decade, but there is no evidence of an increase during this period in the number of Mexican-born migrants returning home from the U.S.

Hispanics now make up 22% of all children under the age of 18 in the United States--up from 9% in 1980--and as their numbers have grown, their demographic profile has changed.

The question of who's Hispanic -- and who isn't -- turns out to be pretty complicated.

There were 11.9 million unauthorized immigrants living in the United States in March 2008. The size of the unauthorized population appears to have declined since 2007.