According to a survey conducted by the International Association of Amusement Parks and Attractions, in 2005, 335 million people visited over 600 amusement parks in the United States, generating $ 11.2 billion in revenue. The attendance in amusement parkas has continued to increase and is projected to continue in a steady growth. In 2004, 28 percent of Americans claimed they had visited an amusement park and one half had plans to do so in 2006.