38 million credit cards were linked to Apple Pay in China on the first day

"According to local reports, by 5 p.m., 38 million bank cards had been linked to Apple Pay. The Beijing Morning News said on its Weibo account that within an hour of the service going live at 5 a.m., 10 million people had already linked their bank cards to their accounts."

Source:  Mashable, 19th February 2016