Retail employment experienced a net gain of 646,300 jobs between October and December, according to a Challenger, Gray & Christmas Inc. analysis of employment data released today by the U.S. Bureau of Labor Statistics (BLS). That is a 28.9 percent improvement over 2009, when seasonal hiring led to 501,400 net new jobs. The analysis conducted by Challenger, a Chicago-based outplacement firm, found that though November hiring was about the same as a year earlier, October and December hiring were the heaviest they’ve been in several years. Last month, retail employment grew by 181,900 positions, which is the largest December gain since 2005. October’s increase of 146,800 retail jobs was the largest for that month since 2006. The BLS report said that retail employment increased by a seasonally adjusted 12,000 jobs. The Challenger report used non-seasonally adjusted data provided by the BLS.