WASHINGTON (AP) - The number of people seeking U.S. unemployment benefits rose 15,000 last week to a seasonally adjusted 309,000. But the data was distorted for the second straight week by reporting delays. The Labor Department says the level is only slightly above the previous week's 294,000, the lowest in six years. Applications plummeted two weeks ago when California and Nevada were unable to report all their applications of computer upgrades in both states. A government spokesman says those states reported all the applications that came in last week. The broader trend in applications has been favorable, signaling fewer layoffs. The less volatile four-week average fell 7,000 to 314,750, the lowest in nearly six years. But backlogged applications from two weeks ago may elevate the figures in the coming weeks, he said.