Despite the challenges, baby boomers are taking over a growing share of business start-ups, even as overall rates of entrepreneurship decline.

Over the decade ended in 2013, boomers ages 55 to 64 went from starting 18.7 percent of new businesses to 23.4 percent, according to the Kauffman Index of Entrepreneurial Activity. Some of the increase can be explained by demographics: As baby boomers age, they account for a greater share of just about any pie. Also driving the increase are stubbornly low rehiring rates for jobless older workers.

Gone are the days when older entrepreneurs were mostly people who had finished good careers and were just looking for the freedom to do something different, said Fred Dawkins, author of “Everyday Entrepreneur.”

“Right now we’re dealing with more people who are doing this out of necessity because they’ve been forced out,” Dawkins said.

After a long career in nursing administration and then health care information technology, Bohnne Jones faced her first layoff 12 years ago at age 51. For the next five years she landed three other corporate jobs, but each ended either in mass layoffs or the completion of a major project. During one stint, she ended up redecorating a physicians lounge that was going to house new computers that she had ordered.

The experience rekindled an old passion for interior design.

Ultimately, in 2007, Jones withdrew half her $300,000 individual retirement account to buy and start operating a Decorating Den franchise in Nashville.

“And you know what happens next,” she said, referring to the mortgage crisis and ensuing recession. She ended up investing about $260,000 in total and reduced her business checking account to about $20,000 before the business picked up.

That’s when she had to drop her husband from the payroll, and he enrolled in a truck driver training program.

Her advice to would-be corporate refugees thinking of starting a franchise: Commit more money to the project than you think it will take.