U.S. manufacturing expanded slightly less than previously thought in December, according to revised data released by an industry group on Wednesday.

The Institute for Supply Management said its index of national factory activity came in at 54.9 versus the 55.9 it originally reported for December.

Meanwhile, U.S. non-manufacturing activity contracted slightly in December instead of expanding almost imperceptibly as first reported.

The ISM revised its non-manufacturing index to 49.8 last month versus the 50.1 originally reported for December.

The level of 50 separates expansion from contraction in the indexes for both the factory and service sectors.

Within the manufacturing report, the new orders index was revised down to 64.8 from 65.5 previously reported, while the employment index for December was revised down to 50.2 from 52.0 previously reported.

In the non-manufacturing sector, ISM said its business activity index was revised down to 53.2 in December from 53.7 previously reported.

The non-manufacturing new orders index was revised down to 52.0 in December from 52.1 previously reported, while the employment index was revised down to 43.6 in December from 44.0 previously reported.

The ISM U.S. non-manufacturing prices index was revised up to 59.6 in December from 58.7 previously reported.

(Reporting by Ellen Freilich; Editing by Chizu Nomiyama)