Economic activity in the non-manufacturing sector grew in March for the 87th consecutive month, the Institute of Supply Management reported on Wednesday.

The institute's non-manufacturing index hit 55.2 in March, down from 57.6 in the previous month. This represents continued growth in the non-manufacturing sector but at a slower rate, the group said.

Economist polled by Thomson Reuters had expected the ISM non-manufacturing index to hit 57 in March.

A reading above 50 indicates expansion in the service sector, and a reading below 50 indicates contraction.

Fifteen non-manufacturing industries surveyed reported growth in March, the institute said in its report, including utilities, wholesale trade, mining and real estate. The three industries reporting contraction in March were information, educational services, and professional, scientific and technical services.

"[The] first quarter has been brisk, and March has been as busy as I [have] ever seen, with many new endeavors," one utilities respondent said.

"Health care changes can affect our business," one health-care related respondent told the institute in March. "Uncertainty is making us hold on many projects."

The majority of ISM's survey's respondents' comments indicated a positive outlook on business conditions and the overall economy, the Wednesday report said. However, "there were several comments about the uncertainty of future government policies on health care, trade and immigration, and the potential impact on business."