Economic activity in the U.S. service sector increased in January after contracting in December, according to the Institute for Supply Management's nonmanufacturing index released Wednesday. The readings include updated information from the U.S. Department of Commerce which is used to calculate the index.

The nonmanufacturing index rose to 50.5 in January from a revised reading of 49.8 in December. Readings of more than 50 indicate expansion.

The employment portion of the index rose to 44.6 in January from 43.6 in December. The January number showed a continued decrease but at a slower rate than in December.