Trinidad and Tobago is a parliamentary democracy governed under the constitution of 1976. It has a bicameral Parliament made up of a 31-seat appointed Senate and a 36-seat elected House of Representatives; all members serve five-year terms. The government is headed by a prime minister. The head of state is the president, who is elected by the members of Parliament for a five-year term. Aministratively, the country is divided into 9 regional corporations, 2 city corporations, 3 borough corporations, and 1 ward (Tobago).