Tourism is the industry that provides services for people on vacation. It is considered a tertiary industry that employs more people than any other sector. In 2003, there were over 691 million international tourist arrivals that generated $523 billion in receipts. Many less economically developed countries see tourism as an opportunity for economic development and it contributes a large percentage to their GDP. The most popular international destinations in 2005 were France, Spain, the United States, Italy, and China, although factors like weather, currency exchange rates, and events can impact tourism numbers.