The 2015 Southeast Asian Games , officially known as the 28th Southeast Asian Games , was a Southeast Asian multi-sport event hosted by the city-state of Singapore. It was the fourth time the country hosted the games and the first time since 1993. Singapore previously also hosted the games in 1973 and 1983. Singapore was awarded rights to host the Southeast Asian Games in 2011 after several delays from 2007 due to the construction of the New National Stadium. The games were held from 5 to 16 June 2015, although several events had commenced from 29 May 2015. Around 4370 athletes participated at the event, which featured 402 events in 36 sports. It was opened by Tony Tan Keng Yam, the President of Singapore at the aforementioned stadium. The final medal tally was led by Thailand, followed by host Singapore and Vietnam. Several Games and national records were broken during the games. Though there were little controversies, the Games were deemed generally successful with its effective management of cost spent to host the games, arrangement of public transport and games promotion and with the rising standard of competition amongst the Southeast Asian nations.
Question: How many years has it been since Singapore last hosted the Southeast Asian Games?
Answer: 3