BEIJING -- China's chain convenience stores grew steadily in number and sales last year, a report showed.

The number of chain convenience stores reached about 106,000 last year, up 13 percent year on year, according to a report released by the China Chain Store and Franchise Association (CCSFA) and Boston Consulting Group.

Total sales exceeded 190 billion yuan ($29.75 billion) in 2017, up 23 percent year on year, the report showed.

The report pointed out that China's convenience stores face rising costs while their gross margins still lag behind leading international players.

Chinese convenience stores are increasing investment in new retail and logistics technology to reduce costs and increase efficiency, the report showed.

Another report by CCSFA showed that Changsha, capital city of Hunan Province, posted the strongest growth in convenience stores last year, followed by Shenzhen and Taiyuan.