Qatar population was 2.6 million: 313,000 Qatari citizens and 2.3 million expatriates. Islam is the official religion of Qatar. The country has the highest per capita income in the world. Qatar is classified by the UN as a country of very high human development and is widely regarded as the most advanced Arab state for human development. Qatar is a high-income economy, backed by the world's third-largest natural gas reserves and oil reserves. Qatar has been ruled by the House of Thani since Mohammed bin Thani signed a treaty with the British in 1868 that recognised its separate status. Following Ottoman
Udon Thani Province 155 sub-districts ("tambon") and 1682 villages ("muban"): Udon Thani is linked to the rest of Thailand by comprehensive air, road and rail connections. Most of the major highways that run through the northeastern Thailand, including Mittraphap Road, serve Udon Thani as well. Udon Thani International Airport, the province's primary airport, is in the district of Mueang Udon Thani near the border with Nong Khai Province. Between them, several airlines operate over 160 flights per week (as of August 2017) to Bangkok. Udon Thani Railway Station is the main railway station in Udon Thani. Udon Thani has several tertiary education institutions.