The U.S. Census is complete, and results were delivered to President Barack Obama last week.

The nation’s population as of April 1 had reached 308,745,538, according to the U.S. Census Bureau. That represents a 9.7-percent increase from the 2000 population of 281,421,906.

Nationwide, the mail-back participation rate of 74 percent matched that of the 2000 Census and helped save about $1.87 billion in the budget.

“A big thanks to the American public for its overwhelming response to the 2010 Census,” U.S. Commerce Secretary Gary Locke said at a news conference in Washington, D.C., on Tuesday.

Census workers visited those who did not mail in their forms to take the count.

In Suffolk, participation rates came in above the national and state rates. Virginia’s mail-back participation rate was 78 percent, while Suffolk’s was 79 percent — up 1 percent from the last census.

The best participation in the city came from a swath of the northwestern part of the city, including Chuckatuck and much of the Godwin Boulevard corridor. About 85 percent of residents in that area mailed back their forms by the deadline.

The city’s worst participation rate — 64 percent — came from a portion south of the downtown core, stretching from Lake Kilby in the west to County Street on its eastern border, and from Dill Road north almost to Washington Street.

City-level population numbers obtained by the Census will not be available until the spring. However, 2009 estimates pinpointed the number at 83,659 — an increase of more than 31 percent from the 2000 Census, which counted 63,684.

Statewide, Virginia’s population skyrocketed 13 percent from 2000 to slightly more than 8 million. The state now ranks No. 16 in the nation in population density.

Unlike many other states, Virginia will not gain or lose any of its 11 seats in the House of Representatives. Nationwide, each member of the House represents an average of 710,767 people.

Among all 50 states, the most populous was California, with 37.2 million. The least populous was Wyoming, where 563,626 residents were counted — fewer than the estimated 2009 populations for Suffolk, Portsmouth and Virginia Beach combined, but in a state with a land area almost 2.5 times the size of Virginia.