HAIKOU - Sales revenue from an offshore duty-free program in Hainan province totaled 5.54 billion yuan ($842 million) in 2015, according to customs sources.

Haikou customs on Saturday said that the southern island province's two offshore duty-free stores received around 1.64 million customers and sold more than 6.49 million items last year.

Hainan has two duty-free shops, with one in the provincial capital of Haikou and the other, the world's largest, in the resort city of Sanya.

The State Council, China's cabinet, gave Hainan permission to run a trial duty-free program in April 2011 in an effort to make the island a world-class tourist destination by 2020.

Hainan allows non-locals to make duty-free purchases twice a year before leaving the island by plane, with each time capped at 8,000 yuan.

The island province has seen booming tourism since the program started.