A measure of future U.S. economic growth increased last week while the annualized growth rate slowed, 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 131.9 in the week ended December 20 from 130.9 the previous week.

The index's annualized growth rate decreased to 1.9 percent from 2.1 percent a week earlier.