South Carolina's unemployment rate fell to 11 percent during May as the U.S. Census Bureau's efforts entered the most worker-intensive phase of resident counting.

Federal hiring accounted for a large portion of the job growth, which has led the statewide unemployment rate to decline for four consecutive months. The statewide figure in April was 11.5 percent.

Census spokesman Terry Plumb said his agency planned to hire roughly 10,200 workers statewide to visit households that didn't return a government questionnaire.

"It's on a downhill trend now," he said of the bureau's hiring. "It's unfortunate that since they're letting people go, those numbers will probably go the other way."

Private-sector employment in South Carolina remained nearly flat during May, raising questions about whether the state's six-month swell of job growth will continue.

"As census hiring fades in the coming months, South Carolina's employment recovery will face a significant test," research economist Don Schunk wrote in an analysis of the latest numbers Friday.

"Is there enough private-sector momentum building in the economy to keep the recovery moving forward as federal census and stimulus effects wane?"

Schunk also pointed out that the state's labor force continues to shrink, which can send an unemployment rate lower without any fundamental improvements within the economy.

Statewide figures that account for seasonal fluctuations show meager monthly gains of 600 in manufacturing, 1,300 in the financial sector and 400 in professional and business services. Employment fell by 500 in tourism, 500 in construction and 2,200 in transportation, trade and utilities.

South Carolina recorded one of the largest over-the-month job growths behind Delaware, Maine and Rhode Island, according the U.S. Bureau of Labor Statistics. Thirty-seven states saw their unemployment rates fall.

Still, the Palmetto State had the seventh-highest unemployment figure in the country last month.

The jobless rate worsened within the state's top metropolitan areas, including Charleston. The Charleston area's unemployment rate jumped to 8.8 percent from 8.4 percent the previous month, while Columbia and Greenville rates rose to 8.9 percent and 9.5 percent, respectively.

South Carolina's economy began showing better-than-usual monthly job growth last fall, a trend that held through most of spring. Employers were reportedly encouraged by more robust consumer spending and optimistic economic forecasts.

"We are starting to see an uptick in the logistics market, which is of course an indicator of all other markets," said Lisa Stackhouse, who oversees staffing agency Atlanta-based Randstad USA's South Carolina operations.

Company executives turned to temporary hiring firms to stay flexible amid uncertain market conditions, Stackhouse said. That growth is reflected in the statewide professional and business services sector, which has added 16,000 workers during the past year.

Reach Katy Stech at 937-5549 or kstech@postandcourier.com.