Washington, Dec 22 (DPA) The US population grew by 9.7 percent in the last decade to 308.7 million people, but the country's growth rate has slowed, the Census Bureau said Tuesday.

The population grew to 308,745,538 since 2000, the slowest pace of growth since 1930-40.

Census Bureau director Robert Groves said about 60 percent of the increase was from people born inside the US, while 40 percent was those who had immigrated.

The largest increases were in the south and west. In Texas, the population grew by 4.3 million to 25 million. California, the most populous of the 50 states, has more than 37 million people, the Census Bureau said.

Nevada had the highest growth rate for the decade at 35.1 percent, followed by Arizona at 24.6 percent, Utah at 23.8 percent and Texas at 20.6 percent.

The Great Lakes state of Michigan was the only state where the population dropped, by 0.6 percent. The traditional centre of the US automotive industry, Michigan has seen its economy devastated in recent years by the retrenchment among US carmakers.

Census data is used to divvy up the representation of states in the US House of Representatives, and will be used to redraw congressional districts before the 2012 elections.

The US Constitution requires a census to count the entire population every 10 years.

This year, Texas gained four seats in the 435-member House of Representatives and Florida two, while Ohio and New York lost two seats.

The first census was taken in 1790 and has been repeated every 10 years.