BEIJING, June 30 (Xinhua) -- Boosted by a strong service sector, China's non-manufacturing activity expanded at a faster pace in June, adding to signs of a stabilizing Chinese economy, official data showed Friday.

The non-manufacturing purchasing managers' index (PMI) came in at 54.9 in June, up from 54.5 in May, according to the the National Bureau of Statistics (NBS).

A reading above 50 indicates expansion, while a reading below reflects contraction.

For the first half of 2017, non-manufacturing PMI averaged 54.6, higher than the 53.4 during the same period last year, NBS data showed.

The service sector, which accounted for more than half of the country's gross domestic product (GDP) last year, saw robust growth in June, with the sub-index coming in at 53.8, up from 53.5 the previous month.

The strong performance in the service sector was boosted by a mid-year online shopping event, which saw e-commerce giants such as JD.com and Alibaba offer big discounts to customers, according to NBS senior statistician Zhao Qinghe.

Thanks to robust online consumption, the sub-indices for the express mail services and Internet and software information technology services jumped to 72.2 and 61.8 respectively, well above the boom-bust line of 50.

The sub-index for the construction industry reached 61.4 in June, the highest point of this year, as infrastructure investments kept growing fast, Zhao said.

Friday's data also showed that China's manufacturing sector expanded for the 11th straight month in June, with the manufacturing PMI coming in at 51.7 in June, up from 51.2 in May.