The President of the Republic of Singapore is Singapore's head of state. In a Westminster parliamentary system, as which Singapore governs itself, the prime minister is the head of the government while the position of president is largely ceremonial. Before 1993, the President of Singapore was chosen by Parliament. Following amendments to the constitution enacted in 1991, the Presidency became a popularly-elected office. The first President elected by the majority of the people was Ong Teng Cheong, who served from 1 September 1993 to 31 August 1999. The current President of Singapore is Tony Tan Keng Yam.