Singapore Changi Airport hosts a network of over 100 airlines connecting Singapore to some 300 cities in about 70 countries and territories worldwide. It has been rated one of the best international airports by international travel magazines, including being rated as the world's best airport for the first time in 2006 by Skytrax. Singapore Changi Airport also had the second- and third-busiest international air routes in the world; the Jakarta-Singapore airport pair had 4.8 million passengers carried in 2018, whilst the Singapore-Kuala Lumpur airport pair had 4.5 million passengers carried in 2018, both trailing only behind Hong Kong-Taipei (6.5 million). Singapore Airlines, which is the flag carrier of Singapore, has been regarded as a 5-star airline by Skytrax and been in the world top 10 list of airlines for multiple consecutive years. Changi Airport had also been rated as the world's best airport from 2013 to 2020 before being superseded by Hamad International Airport in Doha Sea The Port of Singapore, managed by port operators PSA International and Jurong Port, was the world's second-busiest port in 2019 in terms of shipping tonnage handled, at 2.85 billion gross tons (GT), and in terms of containerised traffic, at 37.2 million twenty-foot equivalent units (TEUs). It is also the world's second-busiest, behind Shanghai, in terms of cargo tonnage with 626 million tons handled. In addition, the port is the world's busiest for transshipment traffic and the world's biggest ship refuelling centre. Industry sectors 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 7th in the Global Innovation Index in 2022. 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. Singapore's largest companies are in the telecommunications, banking, transportation, and manufacturing sectors, many of which started as state-run statutory corporations and have since been publicly listed on the Singapore Exchange. Such companies include Singapore Telecommunications (Singtel), Singapore Technologies Engineering, Keppel Corporation, Oversea-Chinese