U.S. worker productivity rose less than labor costs last month, which could mean that companies will increase prices to make up the difference, reported Bloomberg News.

The U.S. Labor Department revised its figures today to show that worker productivity, a measure of how much an employee produces per hour of work, rose at an annual rate of 1 percent in May, while labor costs rose at a 1.8 percent rate. It also revised its fourth-quarter figures for 2006 to an annualized productivity gain of 2.1 percent and labor cost increase of 8.9 percent.

A change in how the government accounted for bonus payments and stock options last year explains some of the increase in labor costs, which account for about two-thirds of a company’s cost of producing a good or service. Labor expenses for all of last year rose 3.3 percent.