6 million: Estimated number of Americans eligible for Mensa membership. To qualify, an individual must score in the top 2 percent of the general population on an accepted standardized intelligence test. American Mensa, headquartered in Arlington, is the largest national Mensa organization with 57,000 members. (Source: American Mensa)

96,122: Total number of registered nonprofits in 2014, the second highest in the U.S. (Source: National Center for Charitable Statistics)

22,824 Individuals employed by membership associations

National Athletic Trainers’ Association (Carrollton)

Promotional Products Association (Irving)

Society of Petroleum Engineers (Richardson)

American Heart Association (Dallas)

American Gem Trade Association (Dallas)

International Facility Management Association (Houston)

Association of Certified Fraud Examiners (Austin)

American Payroll Association (San Antonio)

Source: Associations Yellow Book, Winter 2015

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