Google can deliver a lot of census data, the question is can it be considered valid. The CIA 2003 World factbook says that Singapore's population is 4,608,595 from a July 2003 estimate, however <http://www.embassyofindia.com/sg_society.htm> states that "Today, Singapore’s population (including permanent residents) is 3.16 million" and of them - "7 percent Sikh"(it's outdated) [also should be 0.7 percent]
(1983): "Sikhs also moved to Malaysia. Today as many as 50,000 Sikhs live in the western part and to the south, in the city-country of Singapore, there are an estimated 20,000 more Sikhs."
(1997): "... The present Sikh population of Malaysia is reckoned to stand at around 40,000-50,000, forming about three per cent of the total Indian community in the nation's population. "
<http://www.google.ca/search?q=cache:M97Ze8UpFJUJ:www.adherents.com/adhloc/Wh_297.html+singapore+sikhs+percent&hl=en&ie=UTF-8>