The Singapore business environment is one of the most business-friendly places in the world. Singapore has a highly developed market-based economy well-respected for its level of free-enterprise, innovation and competitiveness. According to the Corruption Perceptions Index Singapore is also consistently ranked as one of the least corrupt countries in the world. Singapore attracts a great deal of foreign direct investment because of its location, corruption-free environment, skilled workforce, low tax rates and advanced infrastructure. The nation is home to thousands of multinational corporations from the United States, Japan, Europe, China and India. A lot of Singapore business relies on exports and refining imported goods. This includes electronics, petroleum refining, chemicals, mechanical engineering and biomedical sciences sectors. Other key sectors include tourism (gaming and medical tourism), education, banking and finance, ship repair, shipping and logistics – amongst others.