Economic activity in the US services sector contracted in December after 30 consecutive months of growth, according to the Institute for Supply Management’s Services PMI. The measure of economic activity in the services sector fell to 49.6% in December from a reading of 56.5% in November.

December’s reading indicated the overall economy is contracting. Readings above 50.1% in the Services PMI over time generally indicate an expansion of the overall economy.

“Of the four subindexes that directly factor into the Services PMI, three — new orders, employment and supplier deliveries — contracted in December,” said Anthony Nieves, chair of the ISM services business survey committee. “Prior to the current contraction in the services sector, the PMI indicated growth for all but two of the previous 154 months, including a faster rate of expansion in November.”

The employment subindex contracted to 49.85 in December from 51.5% in November.

“Employment contracted due to a combination of decreased hiring due to economic uncertainty and an inability to backfill open positions,” Nieves said.

The ISM’s index is based on data compiled from a survey of purchasing and supply executives across the US.