Groundbreaking for U.S. single-family homes rose in December to the highest level in more than 6-1/2 years and permits surged, in a hopeful sign for the sluggish housing market recovery. The Commerce Department said on Wednesday single-family housing starts, the largest part of the market, jumped 7.2 percent to a seasonally adjusted annual pace of 728,000-units – the highest level since March 2008.