Singapore, officially the Republic of Singapore, is a sovereign city-state and island country in Southeast Asia. It lies off the southern tip of the Malay Peninsula and is 137 kilometres (85 mi) north of the equator. Made up of the lozenge-shaped main island and over 60 much smaller islets, it is separated from Peninsular Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the Singapore Strait to its south. The country is highly urbanised, with very little primary rainforest remaining. Its territory has consistently expanded through land reclamation. Singapore is one of the world's leading commercial hubs, with the fourth-biggest financial centre and one of the five busiest ports. Its globalised and diversified economy depends heavily on trade, especially in manufacturing, which constituted 26 percent of Singapore's GDP in 2005. In terms of purchasing power parity, Singapore has the third-highest per capita income in the world.