Singapore is the world's 3rd-largest foreign exchange centre, 6th-largest financial centre, 2nd-largest casino gambling market, 3rd-largest oil-refining and trading centre, largest oil-rig producer and hub for ship repair services, and largest logistics hub. The economy is diversified, with its top contributors being financial services, manufacturing, and oil-refining. Its main exports are refined petroleum, integrated circuits, and computers, which constituted 27% of the country's GDP in 2010. Other significant sectors include electronics, chemicals, mechanical engineering, and biomedical sciences. Singapore was ranked 8th in the Global Innovation Index in 2020, the same as 8th in 2019.  In 2019, there were more than 60 semiconductor companies in Singapore, which together constituted 11% of the global market share. The semiconductor industry alone contributes around 7% of Singapore's GDP.