The U.S. services sector posted its 11th straight month of growth Monday, but the results fell short of economists' expectations, supporting the prevailing notion that the economy is on a slow pace to recovery.

The Institute for Supply Management said its index on nonmanufacturing activity fell to 54.7 in December from 57.4 in November. Economists, on average, were projecting a reading of 55.9, according to

. Any reading over 50 typically signals expansion in the sector. The data revealed that new orders grew at a slower rate than in November and that the job market remains soft.

The services sector makes up a large portion of the nation's economy, and it includes a wide range of businesses. Reports from purchasing and supply executives indicated that seven industry groups grew in December, six groups contracted and four industry groups reported no change from November. The industries reporting the highest rates of growth in business activity in December were agriculture, real estate, business services, health services and retail trade. The weakest industries were wholesale trade, public administration, utilities, construction and finance and banking.