WASHINGTON—U.S. worker productivity rebounded more than expected in the fourth quarter, curbing labor costs growth, but the coronavirus pandemic has distorted the data and prevented a clear trend. The Labor Department said on Thursday that nonfarm productivity, which measures hourly output per worker, increased at a 6.6 percent annualized rate last quarter. Data for the third quarter was revised up to show productivity declining at a 5.0 percent rate instead of the previously reported 5.2 percent pace. Economists polled by Reuters had expected productivity would rebound at a 3.2 percent rate. Productivity has been volatile since the pandemic started in the United States three years ago. Compared to the fourth quarter of 2020, productivity grew at a 2.0 percent pace. Productivity increased at a 1.9 percent rate in 2021, slowing the 2.4 percent growth logged in 2020. Hours worked rose at a 2.4 percent rate last quarter, pulling back from …