The gig economy is great for Uber and Postmates, but not for their workers, according to a new survey.

Sixty-seven percent of contractors surveyed by Deloitte would choose not to work a contract job in the future. The consulting company on Thursday released the results of the survey, covering 4,000 full-time, part-time and independent contractors in 13 US markets.

While the online survey applied to workers across a variety of industries, it's especially relevant to tech. The business model in which a company employs a large number of independent contractors, rather than hiring full-time employees, has taken over Silicon Valley. It's been key to the success of Uber with its roster of drivers, Postmates with its fleet of delivery drivers and Instacart with its grocery deliverers.

Companies who categorize their workers as contractors rather than employees don't have to provide the same workplace protections or benefits.

That has led to problems for both workers and their companies. Uber is tied up in a lawsuit surrounding the question of whether its drivers should be considered contractors or employees. The 385,000 drivers who signed on to that lawsuit — and perhaps the 67 percent of surveyed contractors — would likely say they are employees.

While most workers said they didn't want to do contract jobs again, almost half of them were at least happy with the work they did. In Deloitte's poll, just under half of the contractors surveyed said they were "very satisfied" with their contract work experience.

Only 34 percent of all workers surveyed said they would consider working fully independently. Sixty percent thought their stability would suffer if they moved to independent contract work.

Unsurprisingly, more than half of Deloitte respondents said the most important benefit of full-time work was a steady income.

Deloitte concluded from its results that companies have more to do to attract independent contractors. And despite the negative attitude of contractors toward their work experiences, it clearly sees the trend toward contract work sticking around. Deloitte calls its poll the "Evolving Workforce Survey."

It offered guidance for companies in creating a company culture appealing to independent workers.

"In order to achieve business goals, organizations should look to attract all talent pools. Organizations should start thinking about the culture they have in place and the experiences they can design for contingent workers," Deloitte's chief talent officer, Mike Preston, said in a statement accompanying the results.

The gig economy is forecasted to reach 54 million independent workers by 2020.