The country is a kingdom, a constitutional monarchy with King Bhumibol Adulyadej, the ninth king of the House of Chakri, who has reigned since 1946, making him the world's longest-serving current head of state and the longest-reigning monarch in Thai history. The king is officially titled Head of State, the Head of the Armed Forces, an Upholder of the Buddhist religion, and the Defender of all Faiths.
The largest city in Thailand is Bangkok, the capital, which is also the country's center of political, commercial, industrial and cultural activities.
Thailand is the world's 50th largest country in terms of total area (slightly smaller than Yemen and slightly larger than Spain), with a surface area of approximately 513,000 km2 (198,000 sq mi), and the 20th most-populous country, with approximately 66 million people. About 75% of the population is ethnically Thai, 14% is of Chinese origin, and 3% is ethnically Malay; the rest belong to minority groups including Mons, Khmers and various hill tribes. There are approximately 2.2 million legal and illegal migrants in Thailand. Thailand has also attracted a number of expatriates from developed countries. The country's official language is Thai. Its primary religion is Buddhism, which is practiced by around 95% of all Thais.
