By John S. McClenahen Last week the number of initial claims for unemployment insurance in the U.S. fell to 331,000, some 3,000 fewer than the previous week's revised figure of 334,000, the U.S. Labor Department reported on Aug. 19. The department's four-week moving average of initial claims, which smoothes out week-to-week variations and is considered a better indicator of underlying labor market conditions, also declined last week, down 2,500 to 337,000. "The Labor Department noted that the impact from Hurricane Charley was negligible, but that we could see the impact [of the storm] filter through [the numbers] in the coming weeks," relates Merrill Lynch & Co., New York. Merrill now figures the Labor Department's Sept. 3 report on U.S. employment in August will show that 150,000 nonfarm jobs were created this month. If so, that would be just enough to keep pace with the average monthly increase in the size of the civilian workforce.