Christianity forms the second-largest religion group in the province, forming around 14.67% of the total population. The two largest Christian domination in the Riau Islands are Protestantism and Catholicism, forming around 12.21% and 2.46% of the total population respectively. Most of the people who adhered Protestantism are from Batak sub-groups (specifically Batak Toba, Karo and Simalungun), Nias, Chinese, and immigrants from North Sulawesi, Maluku and Papua, while most of the people who adhered Catholicism are immigrants from East Nusa Tenggara. The province does not have its own Catholic Diocese. Instead, it is served by the Roman Catholic Diocese of Pangkal-Pinang, which is based in Pangkal-Pinang, Bangka Belitung Islands.