Associated Press

WASHINGTON—Hispanics accounted for more than half of the U.S. population increase over the last decade, exceeding estimates in most states, while America's population center edged westward on a path to leave the Midwest.

The Census Bureau on Thursday will release 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 increased suburbanization were the predominant story lines. Geographers estimate that the nation's population center will move southwest about 30 miles and be placed in or near the village of Plato in Texas County, Mo.

"There is excitement," said Brad Gentry, 48, of Houston, Mo., who publishes the weekly paper in Texas County, noting that the U.S. population center typically carries symbolic meaning as the nation's heartland. "It is putting a spotlight on a corner of the world that doesn't get much attention. Most residents are proud of our region and like the idea that others will learn our story through this recognition."

Racial and ethnic minorities are expected to make up an unprecedented 90% of the total U.S. growth since 2000 because of immigration and higher birth rates for Latinos.

Based on 2010 census data that has been released so far on a state-by-state basis, the number of Hispanics is now at roughly 47 million, with figures for New York, Maine and the District of Columbia to come later Thursday. The 2009 census data estimated the Hispanic count in those places at more than three million, putting Hispanics on track to exceed 50 million. Demographers widely believe the 50 million threshhold will be reached, with a total count close to 50.5 million.

Currently the fastest-growing group, Hispanics now account for one in six Americans; among U.S. children, Hispanics are roughly one in four.

According to a Pew Hispanic Center analysis, the 2010 count of Hispanics was on track to be 900,000 higher than expected, as their ranks surpassed census estimates in roughly 40 states. Many of their biggest jumps were in the South, including Alabama, North Carolina and Louisiana, where immigrants made large inroads over the last decade.

Asians for the first time had a larger numeric gain than African-Americans, who remained the second-largest minority group, at roughly 37 million. Based on the 2010 census results released by state so far, multiracial Americans were on track to increase by more than 25%, to about roughly 8.7 million.

The number of non-Hispanic whites, whose median age is now 41, edged up slightly to 197 million. Declining birth rates meant their share of the total U.S. population dropped over the last decade from 69% to roughly 64%.

"This really is a transformational decade for the nation," said William H. Frey, a demographer at Brookings Institution who has analyzed most of the 2010 data. "The 2010 census shows vividly how these new minorities are both leading growth in the nation's most dynamic regions and stemming decline in others."

"They will form the bulk of our labor-force growth in the next decade as they continue to disperse into larger parts of the country," he said.

The final figures come as states in the coming months will engage in the contentious process of redrawing political districts based on population and racial makeup, with changes that analysts believe will result in more Hispanic-majority districts.

The population changes will result in a shift of 12 House seats and electoral votes affecting 18 states beginning in the 2012 elections. Most of the states picking up seats, which include Texas and Florida, are Republican-leaning, even as most of their growth is now being driven largely by Democrat-leaning Hispanics.

Among other findings:

—In at least 10 states, the share of children who are minorities has already passed 50%, up from five states in 2000. They include Mississippi, Georgia, Maryland, Florida, Arizona, Nevada, Texas, California, New Mexico and Hawaii.

—Over the last decade, Latino population growth was most rapid in the South, where many states have seen Latino populations double since 2000. For the first time, Hispanic population growth outpaced that of blacks and whites in the region, changing the South's traditional "black-white" image.

—More than half of the cities with the largest African-American concentrations showed black population declines in the last decade, including Chicago and Detroit. In contrast, the suburbs of growing southern metro areas like Atlanta, Dallas and Houston saw some of their highest gains.

The Census Bureau calculates the mean U.S. population center every 10 years based on its national head count. The center represents the middle point of the nation's population distribution—the geographic point at which the country would balance if each of its 308.7 million residents weighed the same.

Plato, with a population of 109, is roughly 30 miles southwest of the present mean center in Phelps County, Mo. Based on current U.S. growth, which is occurring mostly in the South and West, the center of population is expected to cross into Arkansas or Oklahoma by midcentury.

The last time the U.S. center fell outside the Midwest was 1850, in the eastern territory now known as West Virginia. Its later move to the Midwest bolstered the region as the nation's cultural heartland in the 20th century, central to U.S. farming and Rust Belt manuf