How much of a toll those benefitless jobs will take on retirement income depends on how long people in that age group spend in them. But it can cost them as much as 26 percent of the income they would have had in retirement compared with people who spent their 50s and early 60s in jobs that came with full benefit packages.

The difficulty of finding traditional jobs for that age demographic, coupled with the likelihood of being shed in favor of a younger employee whose salary is considerably lower, is nudging more and more older workers into the gig economy, but while such jobs provide income when otherwise none is to be had, they can exact a toll in other ways.

In fact, for workers who manage to spend most of their older working years in traditional jobs, with occasional ventures into the gig economy, retirement income only suffers by about 6 percent rather than the 26 percent faced by those who work in nontraditional jobs for those last years of their careers.

And with money often in considerably shorter supply than in traditional jobs that come with benefits, it's not as if gig workers can stretch their incomes to save for retirement or fork over premiums for health coverage.

"I was not only surprised, I was also saddened" by the research, Munnell said in the report, adding, "The results mean that people have to worry about getting protections on their own, and that they have very unpredictable work lives."