Fueled by population growth in coastal regions such as Beaufort County, the state is growing faster than the nation as a whole and beating forecasters' expectations.
The state had 4,774,839 residents on July 1, an increase of 51,422, or 1.1 percent, from July 2012, according to U.S. Census Bureau data released Monday. That makes the state the 11th fastest-growing in the country.
Much of the rise is credited to a population influx in the Lowcountry, according to state demographer Mike MacFarlane of the S.C. Office of Research and Statistics.
"It's been the area that has maintained growth for a long period of time," he said Tuesday. "It weathered the recession better than we anticipated and saw a continued increase."
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Beaufort County has been part of that growth, he said.
The county saw the fourth-largest population jump in the state from 2000 to 2010, increasing 34.1 percent, according to the Census Bureau.
Last February, the Office of Management and Budget announced for the first time that Hilton Head Island-Beaufort-Bluffton was large enough to be classified as a metropolitan statistical area, one of 381 in the nation.
From July 2011 to July 2012, the Census Bureau says, the area's population increased from 189,749 to 193,882. That was a 2.2 percent change, which made the area the 18th fastest-growing in the country.
MacFarlane attributed the population boost to a migration of retirees and the subsequent businesses and service workers they attract.
But will such an increase continue in the Lowcountry?
"Who knows how long it will last?" he said. "What originally drew people there will eventually go away. You'll start having the same traffic problems and things as other places. That's what happened to Florida years ago and caused everyone to look elsewhere for retirement."
Overall, the state's increase suggests it's on track to surpass a projection by his office that the population will reach 4.8 million in 2015, he said.
South Carolina has added 138,478 residents since 2010, and the state's growth rate in the year starting July 1, 2012, topped the nation's population growth rate of 0.7 percent, according to the census.
During that period, only nine states and the District of Columbia grew faster than South Carolina.
North Dakota, the fastest-growing state, is the only state whose population increased by more than 3 percent, followed by the District of Columbia, where the population increased by 2 percent.
Only two states, Maine and West Virginia, saw their populations decrease slightly in the same period, losing a combined 2,575 residents.
South Carolina remained the nation's 24th largest in population.
By New Year's Day, the United States' population will reach 317.3 million, up 2.2 million from the previous year, according to census projections.
The world population is expected to reach 7.1 billion on New Year's Day, up 77.6 million, or 1.1 percent, from the previous year.
India's population grew by 15.6 million last year, leading all countries,followed by China, Nigeria, Pakistan and Ethiopia.
The State's Jamie Self contributed to this report. Follow reporter Dan Burley at twitter.com/IPBG_Dan.