The study conducted by CareerBuilder and Economic Modeling Specialists International found that the recession, which ended in June 2009, set self-employment back by 936,000 jobs.
In 2013, there were 10 million self-employed jobs or 6.6 percent of the jobs total. That is a decline from 7.2 percent in 2006, CareerBuilder said.
The definition of a self-employed worker CareerBuilder used for the study was a person who considered self-employment to be a significant part of their income. But CareerBuilder did not include freelance workers who have smaller, secondary sources of income or owners of incorporated businesses.
CareerBuilder's Chief Executive Officer Matt Ferguson said he expected self-employment opportunities to rebound as the general economy recovers. "As full-time employment in traditional workplaces continues to improve, we expect entrepreneurial opportunities to follow suit with time," he said.
The study found that self-employment jobs have dropped by 5 percent in the past four years. Since the 2006 peak, self-employment jobs have declined by 9 percent, CareerBuilder said.
The strategy of getting a second and third job, however, is flourishing. Twenty percent of full time workers found a second job in 2013 or had plans to do so in 2014, the study found.
The study found that men make up 62 percent of the ranks of self-employed workers and that more than 30 percent of people considering themselves self-employed are 55 years of age or older.
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