The Census Bureau is releasing on Thursday its first set of national-level findings on race and migration from the 2010 count, which will detail a decade in which rapid minority growth, aging white people and increased suburbanization were the predominant story lines.

Racial and ethnic minorities were expected to comprise an unprecedented 90 percent of the total US growth since 2000, due to immigration and higher birth rates for Latinos. Currently the fastest growing group, Hispanics are on track to exceed 50 million, or roughly 1 in 6 Americans; among US children, Hispanics are now roughly 1 in 4.

Based on 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, Louisiana and North Carolina, where immigrants made large inroads during the past 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 states so far, multiracial Americans were on track to increase by more than 25 percent, 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 US population dropped over the last decade from 69 percent to roughly 64 percent.

“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.

Latino population growth during the past decade was most rapid in the South, where many states have seen their 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 “white-black” image.

The final figures come as states in coming months 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 seats in the US House of Representatives, where a state’s representation depends on its populationo.

The changes also will alter the number of presidential electoral votes in 18 states. Those are cast by state delegates based on the state’s representation in the House plus its two US Senate members. Most states picking up electoral seats, which include Texas and Florida, are Republican-leaning, even as most of their growth is now being driven largely by Democratic-leaning Hispanics.

— Online: www.census.gov