The U.S. service sector economy expanded during December, the Institute for Supply Management said today.

The ISM non-manufacturing index rose to a reading of 63.1% from 61.3% in November. This is the highest level since July.

The rise was unexpected, as economists had forecast the index to fall back to 58.5%.

Within the index, employment slipped slightly to 54.9% from 55%.

Also making a slight move, December’s new orders rose to 60.3% in December from 59.9% in the previous month, the ISM’s data showed.

Thirteen of 17 industries were expanded in December, with two contracting.

Readings over 50% in the ISM index indicates expansion in the sector.

Meanwhile, the prices paid index rose to 71.4% from 71%, with 38% reporting higher prices.