The U.S. construction spending posted a scant increase in December 2013, adding more uncertainties to the housing market recovery, U.S. Department of Commerce said on Monday. Total construction spending rose by a moderate 0.1 percent from the revised November data to a seasonally adjusted annual rate of about 930.5 billion U.S. dollars in December. It was 5.3 percent higher than the year-ago estimate. In December, spending on private construction was at a seasonally adjusted annual rate of 663.9 billion dollars, 1.0 percent above the revised level of November. Residential construction rose 2.6 percent, while non-residential construction edged down 0.7 percent on a month-over-month basis. The estimated seasonally adjusted annual rate of public construction spending was 266 billion dollars in December, down 2. 3 percent from the revised November estimate. Home sales stalled in recent months as housing prices and mortgage rose. The National Association of Realtors (NAR) said its index of pending home sales, which measures the number of contracts that have been signed but not yet closed for purchasing previously owned homes, fell 8.7 percent to 92.4 in December, the lowest level since October 2011.