A measure of future U.S. economic growth rose modestly last week, though the annualized growth rate pulled back to a four-week low, a research group said on Friday.

The Economic Cycle Research Institute, a New York-based  independent forecasting group, said its Weekly Leading Index  rose to 124.1 in the week ended April 20, from 123.8 the previous week. That was originally reported as 123.9.

The index's annualized growth rate slipped to 0.6 percent from 1.2 percent.