WASHINGTON (MarketWatch) — Private-sector employers added the most jobs in more than a year in December, with gains across a variety of business sizes and sectors, according to data released Wednesday.

Private employers added 238,000 jobs last month, the most since November 2012, Automatic Data Processing Inc. reported. Trends also show improvement: Private employers added an average of 224,000 jobs per month in the fourth quarter, slightly up from an average of 211,000 during the year-earlier period.

“It appears that businesses are growing more confident and increasing their hiring,” said Mark Zandi, chief economist of Moody’s Analytics, which prepares the report using ADP’s data.

Stock futures slipped despite the strong report.

For all of 2013, ADP says that private employers added 2.16 million jobs, up from 1.96 million in 2012, but down from 2.5 million in 2011.

Notably, ADP’s private-employment showed that goods producers added 69,000 jobs in December, the most since 2006, supported by the housing market’s recovery.

“This sharp gain comes despite unfavorable weather conditions over the month,” Neil Dutta, head of U.S. economics at Renaissance Macro Research, said.

Meanwhile, service providers added 170,000 spots, up slightly from the year-earlier period.

Looking at private employers by size, small businesses added 108,000 jobs in December, while large businesses added 71,000 and medium businesses added 59,000.

The improving data on private-sector jobs has been echoed by a variety of other recent labor-market reports. Recent gauges of services and manufacturing firms show hiring is picking up, and businesses are increasing investment in durable goods, reflecting their confidence in the economy. Indeed, even workers are feeling secure enough to leave their jobs, with a recent report showing that quitting is on the rise.

Still, there’s room for improvement. Despite steadily adding jobs for more than three years, the U.S. economy has almost 1.3 million fewer nonfarm positions, which include private and government spots, than when the recession began at the end of 2007.

Economists use ADP’s data to get a feeling for the U.S. Labor Department’s nonfarm employment report, which will be released Friday. Economists expect the government’s report to reflect that unusually bad weather conditions dampened hiring in December, with nonfarm employment rising by 190,000 jobs, compared with an increase of 203,000 jobs in November.

Economists had forecast that ADP’s report would show private-sector employers added 215,000 jobs last month, matching a prior estimate for November. On Wednesday ADP revised November’s gain to 229,000.

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