The National Association of Professional Employer Organizations, the trade group for PEOs, is in its 25th year this year.

Twenty staff leasing companies gathered in 1984 in Scottsdale AZ to form the National Staff Leasing Association, which became NAPEO in 1994, according to the organization.

"No one knows who started the first PEO or what year it occurred, but history recognizes the 14 people who founded our organization and defined the industry," said Milan Yager, executive VP of NAPEO. "But without NAPEO, the PEO industry today would not be able to acknowledge the 34 states with comprehensive statutes that define the business, identify services and clarify employment responsibilities."

NAPEO is holding a silver anniversary celebration at its annual conference, which begins Sept. 10 in Miami.