WASHINGTON (MarketWatch) -- Job openings at U.S. workplaces 3.99 million in December, the U.S. Department of Labor reported Tuesday. Compared with same period in the prior year, December's job openings rose 10%, as private-sector openings increased 13% to 3.64 million, and government positions fell to 346,000 from 377,000. With 10.35 million unemployed people in December, there were about 2.6 potential job seekers per opening -- the lowest ratio since August 2008 -- compared with 2.7 in November. In December 2012, there were 12.27 million unemployed people -- about 3.4 potential seekers per opening. When the recession began in December 2007, there were less than two potential job seekers per opening. The number of separations, such as quits and layoffs, rose to 4.37 million in December from 4.28 million in November. Meanwhile, the total number of hires declined to 4.44 million from 4.53 million. The level of hires was almost 5 million when the recession began.