Due to the intermittent nature of freelancing and contract work, not only are those engaged in such work having a tough time accessing benefits that many regularly employed workers might take for granted, but a substantial number are not only not prosperous, but even if they have a retirement plan they find it difficult to set money aside for the future.

If you consider that a total of 47 percent of freelancers are either "just okay," "not doing well" or "not doing well at all," that's a pretty sad state of affairs for nearly half of those dependent on the gig economy for their living.

In addition, even though a sizeable percentage of freelancers overall reports being financially well, 4 in 10 freelancers do not have an active, formal retirement plan.

Asked why not, 38 percent say they do not generate enough income to save; 31 percent say it's because they don't get paid on a predictable basis, making it harder to set aside money; 12 percent say it's because plans are too expensive; and 8 percent say there are no good retirement options for freelancers.

And it's something they worry about. More than half of freelancers (52 percent) say the lack of an employer-sponsored retirement plan was a concern when considering freelancing or becoming a solo entrepreneur.

That's pretty major, considering the percentages who reported being worried about losing other employer-sponsored benefits like health care (54 percent), and their ability to generate work (63 percent).

Seventy percent of freelancers say that saving for retirement is a concern, and a third say it is a major concern.

That's comparable to other financial concerns plaguing the self-employed, including the cost of health coverage (74 percent are concerned), the rate of taxation (72 percent), inconsistent cash flow (67 percent), having enough income to cover sick days or medical leave (50 percent) and more.

So what's the solution? Flexibility. Seventy-nine percent of freelancers say they're interested in a flexible retirement savings plan that's portable across employers and can accommodate intermittent contributions.

And among both younger and older workers, the numbers are even higher, with 91 percent of younger workers and 87 percent among older workers who depend on retirement work for more than half of their income.

A big 83 percent say a plan that allows you to withdraw without penalty in order to increase your financial flexibility would make them more likely to save for retirement.

Other plans that could boost participation include automatic investment features, such as the ability to adjust investments based on your age (74 percent) and a plan that includes an automated streamlined process to contribute to a retirement plan during the process of paying quarterly taxes (72 percent).