Productivity in the U.S. nonfarm business sector rose at an annual rate of 4.3 percent in the second quarter, according to the revised data reported by the Labor Department Thursday.

The much stronger rate nearly doubled the preliminary estimate of 2.2 percent reported by the department on Aug. 8, and was higher than the 2.6 percent rate registered in the first quarter.

Compared with the same period last year, productivity in the nonfarm business sector increased by 3.4 percent in the April-June period.

Meanwhile, labor cost pressures eased in the second quarter.

Employers' unit labor costs, or costs of wages and benefits for each unit of output, declined by 0.5 percent at an annual rate, slightly better than expected.

Labor costs in the first quarter had also been revised to a 1.2 percent gain, much lower than the 2.5 percent increase previously reported.

Increases in labor costs, which account for two-thirds of a company's production costs, are good for workers, but could make the Federal Reserve worry about inflation.

Growth in productivity allows companies to pay their workers more without having to raise the prices of their products, which could fuel inflation.