The U.S. four-week moving average of initial claims for unemployment insurance edged down by 500 in the week ended May 18 to a level of 339,500 from the previous week’s revised average of 340,000, according to seasonally adjusted numbers released today by the U.S. Department of Labor.

The four-week moving average decreases the volatility of the weekly numbers. Total initial claims for unemployment insurance for the week were 340,000, down 23,000 from the previous week’s revised figure of 363,000.