Bhutan is governed under the constitution of 2008. The hereditary monarch, the Druk Gyalpo (Dragon King), is head of state; the government is headed by a prime minister. The national Parliament, which was established in 2008 and replaced the unicameral National Assembly, comprises two houses. The upper house, the National Council, has 20 elected members and 5 members nominated by the monarch. The lower house, the National Assembly, has 47 members, all of whom are popularly elected. Administratively, Bhutan is divided into 20 districts (dzongkhag).