Bangladesh elects on national level a legislature with one house or chamber. The unicameral Jatiyo Sangshad, meaning national parliament, has 350 members of which 300 members are directly elected through a national election for a five-year term in single-seat constituencies while 50 memberships are reserved for the women who are selected by the ruling party or coalition. The Prime Minister is the head of the government. The president who is the head of the state is elected by the National Parliament. The president of Bangladesh is a ceremonial post and does not exercise any control over the running of the state. Bangladesh has an unofficial two-party system which has evolved over time since the election of 1991. It means that there are two dominant political parties or coalitions, one headed by Bangladesh Awami League and the other by Bangladesh Nationalist Party, with extreme difficulty for anybody to achieve electoral success under the banner of any other party in terms of achieving a majority. Historical Overview The constitution was adopted in 1972 and declared Bangladesh as a parliamentary republic. However, in 1975 executive powers were transferred to the Presidency, reducing the Jatiyo Sangshad and the Prime Minister to legislative powers only. This system was maintained until 1991 when the Twelfth Amendment was passed, returning the state to a parliamentary system. Since 1971, 11 parliamentary elections have been held and three Presidential elections have been held by popular vote. Parliamentary elections Electoral system The Parliament of Bangladesh (Jatiya Sangsad) consists of 350 members elected to five-year terms. Of that number, 300 are elected in single-member territorial constituencies according to the first-past-the-post electoral system. The remaining 50 seats are reserved for women, and are filled on the basis of proportional representation by a vote of the 300 members. The number of reserved seats has been revised over the years, increasing from 30 to 45 under the 8th parliament and 45 to 50 under the 9th parliament. General elections Since independence in 1971, 11 general elections have been held in Bangladesh to elect members of the Jatiya Sangsad: 1970 1970 Paskistani general election The 1970 Pakistani National Assembly election was held on 7 December 1970. The total number of voters were 29,479,386. The number of casting votes was 17,005,163 (57.68%), the valid casting votes was 16,454,278. 1970 East Pakistan Provincial Council election The 1970 East Pakistan Provincial Council election was held on 17 December