A measure of future U.S. economic growth rose slightly in the latest week, as did the annualized growth rate, 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 121.9 in the week ended June 29, from 121.7 the previous week. That was originally reported as 121.5.

The index's annualized growth rate rose to -2.9 percent from -3.2 percent a week earlier. That was originally reported as -3.6 percent. Both the index and the growth rate rose to three-week highs.