WASHINGTON (MarketWatch) -- Private-sector-employment gains slowed down in January, as employers added 175,000 jobs, Automatic Data Processing Inc. reported Wednesday. Economists had forecast that private-sector hiring slowed down last month, with employers adding 189,000 jobs, compared with an originally estimated December increase of 238,000, according to a Dow Jones Newswires survey. On Wednesday ADP revised December's gain to 227,000. Economists use ADP's data to get a feeling for the U.S. Labor Department's employment report, which will be released Friday and covers government jobs in addition to the private sector. Economists polled by MarketWatch expect the government's report to show that nonfarm employment rose by 190,000 jobs last month, speeding up after a meager gain of 74,000 jobs in December, when there was unusually harsh weather.