Nearly half of the Inc. 500 were founded in 1998, 1999, or 2000. Those boom years were flush times for raising start-up capital.

• Average Year Founded: 1996
• Companies Founded Since 1998: 48%
• Companies Founded in the Past 10 Years: 84%
• Companies Founded by Partners: 57%
• Companies in Which the Founder's Family Is Involved: 50%
• Companies Funded Entirely With Private Equity: 62%
• Companies Funded With Formal Venture Capital: 7%