Feb. 6 (Bloomberg) -- The productivity of U.S. workers rose more than projected in the fourth quarter as the world’s largest economy expanded, helping to restrain labor costs.

The measure of employee output per hour increased at a 3.2 percent annualized rate, after a revised 3.6 percent gain in the prior three months that was more than initially reported, a Labor Department report showed today in Washington. The median forecast in a Bloomberg survey of economists called for a 2.8 percent advance in the fourth quarter. Expenses per worker decreased at a 1.6 percent pace, more than estimated.

A pickup in demand may induce companies, which have been wringing efficiency gains from existing staff, to take on more employees. A report tomorrow may show payrolls in January increased more than twice as much as the prior month, and the unemployment rate held at a five-year low, according to the median estimate in a Bloomberg survey.