family homes jumped in December, offsetting the previous month's decline, the government reported Tuesday, signaling that home-buying may improve this year after a weak 2014. The Commerce Department said new-home sales increased last month to an annual rate of 481,000, up 11.6 percent from the November sales pace of 431,000 units. Economists expected a smaller December gain. The December gain was not enough to offset flat home-buying during 2014, when only 435,000 new homes were purchased, a modest 1.2 percent improvement from 2013. New home sales account for about 8 percent of the housing market. The growth in December indicated rising sales this year, supported by the combination of strong hiring in recent months and sharply lower mortgage rates. Home prices also are rising at a slower pace, improving affordability for potential buyers.