Thailand is the world's 51st-largest country. It is the 20th-most-populous country in the world,The capital and largest city is Bangkok, which is Thailand's political, commercial, industrial, and cultural hub. About 75–95% of the population is ethnically Tai, which includes four major regional groups: central Thai, northeastern Thai (Khon [Lao] Isan),[2] northern Thai (Khon Mueang); and southern Thai. Thai Chinese, those of significant Chinese heritage, are 14% of the population,[5] while Thais with partial Chinese ancestry comprise up to 40% of the population.[16] Thai Malays represent 3% of the population, with the remainder consisting of Mons, Khmers and various "hill tribes". The country's official language is Thai and the primary religion is Buddhism, which is practised by around 95% of the population.