 224 of the 550 tribes in 28 states operate the 350 Native American gaming enterprises nationwide, and 68% of Native Americans belong to a tribe with gaming operations.According to the Harvard Project on American Indian Economic Development, these enterprises earned $19.4 billion in 2005.As compared to the $4.5 billion earned by Native American gaming revenues in 1995, these enterprises have shown substantial growth in just 10 years.