With no direct taxation, the islands are a thriving offshore financial center. More than 40,000 companies were registered in the Cayman Islands as of 1998, including almost 600 banks and trust companies; banking assets exceed $500 billion. A stock exchange was opened in 1997. Tourism is also a mainstay, accounting for about 70% of GDP and 75% of foreign currency earnings. The tourist industry is aimed at the luxury market and caters mainly to visitors from North America. Total tourist arrivals exceeded 1.2 million in 1997, with 600,000 from the US. About 90% of the islands' food and consumer goods must be imported. The Caymanians enjoy one of the highest outputs per capita and one of the highest standards of living in the world.