WASHINGTON -- Hispanics accounted for more than half of the U.S. population increase over the past decade, exceeding estimates in most states as they crossed a new census milestone: 50 million, or 1 in 6 Americans.
Meanwhile, more than 9 million Americans checked two or more race categories on their 2010 Census forms, up 32 percent from 2000, a sign of burgeoning multiracial growth in an increasingly minority nation.
The Census Bureau on Thursday released its first set of national-level findings from the 2010 count on race and migration, detailing a decade in which rapid minority growth, aging whites and the housing boom and bust were the predominant story lines.
In Franklin County, Hispanics became the majority of the population in the past decade, growing from 47 percent in 2000 to 51 percent in 2010.
The Hispanic community accounted for 59 percent of the growth in the county's population over the decade. The 2010 Census counted 40,004 Hispanics among Franklin County's population of 78,163.
Hispanics also gained ground in Benton County, reaching 19 percent of the population, compared with 12 percent in 2000. Almost 46 percent of Benton County's growth during the decade was Hispanics.
Benton County had 32,696 Hispanics among its 175,177 residents in 2010, according to the census.
Analysts said the results confirmed a demographic transformation under way that is upending traditional notions of racial minorities, political swing districts, even city and suburb.
"These are big demographic changes," said Mark Mather, an associate vice president at the nonprofit Population Reference Bureau. "There is going to be some culture shock, especially in communities that haven't had high numbers of immigrants or minorities in the past."
According to data released Thursday, Americans continued their decadeslong migration to fast-growing parts of the Sun Belt. Their move to big states such as California and Texas as well as fast-growing Mountain West states pushed the nation's mean center of population around 30 miles southwest to a spot near the village of Plato, Mo.
Blacks in search of wider spaces increasingly left big cities such as Detroit, Chicago and New York for the suburbs, typically in the South. Michigan and Illinois had their first declines in the black population since statehood, as many of their residents opted for warmer climates in the suburbs of cities such as Atlanta, Dallas and Houston.
After initial fears of low participation, the 2010 count of the Hispanic population came in 900,000 higher than expected, matching or surpassing census estimates in 37 states, according to the Pew Hispanic Center, a nonpartisan think tank.
Many of the biggest jumps were in the South, including Alabama, Louisiana and North Carolina, where a small but fast-growing Hispanic population was fueled by an influx of immigrants during the housing boom.
Multiracial Americans now make up 2.9 percent of the U.S. population, a steadily growing group -- even if it did not include President Obama, who identified himself only as black on his census form. Obama's mother, Ann Dunham, a white woman from Kansas, married his father, the Kenyan native Barack Obama Sr.
The vast majority of multiracial Americans lived in California, Texas, New York and Hawaii. The most numerous race combinations were white-American Indian or Alaskan Native, white-black and white-"some other race."
In some cases, white Hispanics may be opting to list themselves as multiracial in the "some other race" category, which would put the actual number of multiracial Americans lower than the official tally of 9 million.
In all, racial and ethnic minorities made up about 90 percent of the total U.S. growth since 2000, part of a historic trend in which minorities are expected to become the majority by midcentury.