U.S. nonfarm labor productivity decreased at a 1.9 percent annual rate during the fourth quarter of 2012, according to revised data from the U.S. Labor Department Thursday. The revised rate compared with the 2 percent fall released last month. The decrease in productivity reflected increases of 0.5 percent in output and 2.5 percent in hours worked, during the October-December period last year. Unit labor costs, the ratio of hourly compensation to labor productivity, rose 4.6 percent in the fourth quarter. Productivity measures the amount of output per hour of work. Increasing productivity can slow job creation because companies can produce more without hiring more workers.