WASHINGTON (AP) _ American workers' productivity, a key measure of rising living standards, rebounded in the second quarter for its best showing in a year. However, revisions to prior years showed the productivity boom has been slightly less than previously reported.

The Labor Department reported Tuesday that productivity _ the amount of output per hour of work _ rose at an annual rate of 2.5 percent in the April-June quarter. That compared with a tiny 0.1 percent growth rate in the prior quarter, according to revised figures, which pulled productivity from negative territory, as previously reported, into the positive zone.

The second quarter's performance was better than the 1.5 percent growth rate many analysts were predicting and was the biggest gain since the second quarter of 2000, when productivity jumped by a 6.3 percent rate.

Productivity increased in the second quarter as output edged up at a 0.1 percent rate and hours of all workers fell at a 2.4 percent rate. That was the largest decline in hours since the first quarter of 1991.