In the more than 10 years since the terrorist attacks of September 11, 2001, between 2.5 and three million U.S. soldiers have served in active duty. For many of them, the transition back to civilian life is a difficult one. Veterans who find they don't enjoy, or can't fit into, ordinary working life turn to entrepreneurship at greater rates than the rest of the population.

CreditDonkey.com, a credit card comparison and financial education website, has created an infographic to show the impact of veteran entrepreneurship in real terms. More than 2.4 million U.S. businesses are owned by veterans, about nine percent of all American firms. They employ 5.8 million employees and dole out $210 billion in annual payroll.

Their revenue is no chump change, either. About 78 percent of veteran-owned businesses register sales of $100,000 or more, while more than 38 percent have sales of half a million or more.

Also interesting is the average age of veterans who run businesses. Whereas less than 37 percent of all business owners across the U.S. are 55 years of age or older, slightly more than 75 percent of veteran business owners are at least 55 years old, which may reflect a return to civilian life after a long military career. And as for geographic region, California, Texas and Florida lead the pack in numbers of veteran-owned businesses.

Check out the infographic below for the full picture.

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Related: Entrepreneurship Bootcamp Gives Wounded Veterans a New Life