Bermuda enjoys the highest per capita income in the world, more than 50% higher than that of the US. Its economy is primarily based on providing financial services for international business and luxury facilities for tourists. A number of reinsurance companies relocated to the island following the 11 September 2001 attacks and again after Hurricane Katrina in August 2005, contributing to the expansion of an already robust international business sector. Bermuda's tourism industry - which derives over 80% of its visitors from the US - continues to struggle but remains the island's number two industry. Most capital equipment and food must be imported. Bermuda's industrial sector is small, although construction continues to be important; the average cost of a house in June 2003 had risen to $976,000. Agriculture is limited with only 20% of the land being arable.