U.S. small-business owners believe a U.S. economic recovery is unlikely to accelerate before the second half of 2011 amid worries about issues such as healthcare costs, according to a quarterly survey.

The survey, by human resources services company Administaff Inc, found 21 percent of small-business owners surveyed expect an economic rebound before mid-2011. Nearly half believe it will come in the second half of next year, and almost a third said they were not sure.

Three in four cited the economy as their top short-term concern, followed by government healthcare reform, rising healthcare costs and other factors. When asked about long-term worries, the economy fell to third place behind worries such aspotential tax increases and the expansion of government.

The sluggish economic recovery is widely seen as a key factor in Tuesday's U.S. elections, which could erode or erase the majority of President Barack Obama's ruling Democratic party.

U.S. voters on Tuesday will elect a new House of Representatives and about a third of the Senate, and 37 state governor races will be decided.

The majority of businesses surveyed said they were keeping staff levels and pay at current levels through the end of this year, according to the Administaff survey.

But Administaff said average pay is up 3.2 percent, based on compensation data from 5,700 small- and medium-sized businesses for which it provides human resources services. Bonuses and commissions are also up from a year ago.

Administaff also reported a third-quarter profit on Monday that beat Wall Street estimates.