In 2005, Deborah Ramsey was working as an administrator for a technology consulting firm that was undergoing restructuring, the tail end of a phase of her career that also included jobs in the banking and insurance industry.

“A lot of people were being laid off or leaving. I had been through two big layoffs before, I knew what they smelled like,” she recalls. Ramsey decided to leave voluntarily, spurred by the changing work environment and caregiving responsibilities at home, where she looks after a mentally disabled daughter, an aging mother and mother-in-law, and her husband, a disabled veteran.

At age 52, she was ready for a change. But rather than look for a new job, she became a self-employed entrepreneur — following a passionate interest and opening a natural wellness and spa in her home town of Philadelphia.

Ramsey’s transition underscores an important trend among workers over age 50 who find themselves bounced out of the workforce. Entrepreneurs age 55 to 64 represent a rising share of start-up activity, according to the Kauffman Index of Entrepreneurial Activity, accounting for 23 percent of new entrepreneurs in 2010, up from 14.5 percent in 1996.

The shift comes against a backdrop of continued tough times for older workers, as reflected in last week’s report on April unemployment.

Learn more in my column at Reuters Prism Money.

Tags | Career, entrepreneurs, Jobs, second careers