A measure of future U.S. economic growth eased last week, while the annualized growth rate also waned, a research group said on Friday. 

The Economic Cycle Research Institute, a New York-based  independent forecasting group, said its Weekly Leading Index  slipped to 123.1 in the week ended May 18 from 124.4 the previous week. That was originally reported as 124.5. 

The index's annualized growth rate also fell to 0.1 percent from 0.4 percent a week earlier.