The number of Americans filing for jobless benefits fell last week and layoffs in December were the smallest in 15-1/2 years, pointing to a firmer labor market even as economic growth appears to have slowed sharply in the fourth quarter. Initial claims for state unemployment benefits dropped 10,000 to a seasonally adjusted 277,000 for the week ended Jan. 2, the Labor Department said. Last week was the 44th straight week that claims held below the 300,000 mark, which is associated with a healthy labor market.