According to this article Is Singapore the Perfect Country for Our Times?
Singapore's defining achievement is summed up in the title of its longtime leader Lee Kuan Yew's memoir, From Third World to First. When it split off from Malaysia a half-century ago to become a separate nation of dubious viability, Singapore had little going for it, other than a determination to become whatever it needed to be --
However, I have heard many opinions on the subject. Some people claim that Singapore was a complete backwater and its prosperity now was due to its leaders' competence, while others claim that it was already a wealthy and important port.
How wealthy was Singapore at the time of its independence in 1965? Wealth can be reflected in its GDP/capita (of course with some adjustment to make the number meaningful in today's terms), poverty rate, level of infrastructure, etc.