WASHINGTON - The U.S. population has reached an all-time high and Texas was the big winner among eight states that will gain seats in Congress, according to the first data released from the 2010 census.

The decennial head count shows that the official U.S. population is 308,745,538, nearly 10 percent larger than the 2000 census total of 281,421,906.

The 9.7 percent population growth rate from 2000 to 2010 was the second-lowest of the past century, trailing only the 7.3 percent growth from 1930 to 1940, amid the Great Depression.

Census Bureau Director Robert Groves said he could not estimate how much the current economic woes have contributed to the last decade's slow rate of growth. But William Frey, a demographer with the Brookings Institution, said the economy was a key factor in slowing the growth of legal and illegal immigrants since 2006. "The housing market crashed, jobs were hard to come by, and people stopped coming," Frey said of many immigrants.

Groves said that an estimated 60 percent of the 27.3 million new U.S. residents since 1990 were the products of births to U.S. residents, while the rest stemmed from immigration.

Census data help determine how more than $4 trillion will be divided among state, local, and tribal governments over the next 10 years. The findings also inform public-policy decisions on transportation, public health, senior services, and neighborhood improvements.

In addition to determining how much state and federal funding will go to individual communities for the next 10 years, 2010 census population figures determine which states will gain or lose seats in Congress.

Texas added nearly 4.3 million residents from 2000 to 2010, and that 21 percent growth rate will give the Lone Star State four new members of Congress.

Texas, which has added congressional seats for seven consecutive decades, joins Arizona, Florida, Georgia, Nevada, South Carolina, Utah, and Washington as the states that will gain seats under the new congressional apportionment. Florida will add two seats, and the other states add one apiece.

The shift in the placement of congressional seats is likely to benefit Republicans, since most of the states that are gaining seats are GOP strongholds. In addition, President Obama could have a tougher road to reelection, since the reapportionment changes amount to a loss of six electoral votes in states he carried in 2008.

States that will lose one seat apiece because of population shifts are Illinois, Iowa, Louisiana, Massachusetts, Michigan, and Missouri, along with New Jersey and Pennsylvania. New York and Ohio each will lose two seats.

"As states draw new congressional districts to reflect this shift, we will certainly see more Republicans in the U.S. House," said Rep. Patrick McHenry (R., N.C.), the top Republican on the subcommittee on Information Policy, Census, and National Archives.

California, which leads all states with 53 congressional seats, did not gain one for the first time in its history.

Continuing a decades-long trend, the southern and western regions of the nation grew the fastest, at 14.3 and 13.8 percent, respectively. Nevada led all states, with 35 percent population growth since 2000. Arizona, Utah, Idaho, and Texas rounded out the five fastest-growing states.

The population in the hard-hit Rust Belt region of the Midwest grew only 3.9 percent and the Northeast grew even more slowly, at 3.2 percent. Michigan, whose population dipped by six-tenths of a percent, or nearly 55,000 residents, was the only state that had lost residents since 2000. Puerto Rico, an impoverished territory of the United States, lost nearly 83,000 residents, for a 2.2 percent population decline.

Other states with the slowest growth rates since 2000 were Rhode Island, Louisiana, Ohio, and New York.