BEIJING -- China's service sector activity expanded in May, but at a slower pace, an official monthly survey showed on Monday.

The purchasing managers' index (PMI) for the non-manufacturing sector fell to 53.2 in May, down from 53.4 for April, according to a report released jointly by the National Bureau of Statistics and the China Federation of Logistics and Purchasing.

China's non-manufacturing PMI tracks the business activities of the services and construction sectors. A reading above 50 indicates expansion, while a reading below 50 represents contraction.

Zhao Qinghe, a senior analyst with the NBS, said May's reading indicated China's non-manufacturing sector continued to maintain growth, but at a slower pace.

NBS data showed the service sector sub-index stood at 52, above the expansion/contraction threshold, but down from 52.4 in April, suggesting a slower but stable growth, said Zhao.

The sub-index of business activities for the construction industry in May hit 57.9, up 0.4 percentage points from April, thanks to the government's backing of infrastructure and affordable housing construction.

The sub-index for business activity expectations posted at 59, indicating that non-manufacturing enterprises are still optimistic about the market for the next three months, Zhao said.