Americans crave a guaranteed income for retirement, but only a small minority have purchased an annuity, according to the 2017 “TIAA Lifetime Income Survey” released Tuesday.

Only 13 percent of the 671 non-retired people surveyed by the financial services firm TIAA said they have purchased an annuity, the only retirement product that guarantees an income for life other than Social Security. Another 31 percent said they would be interested.

However, misunderstanding abounds, TIAA said. Only half of those surveyed said they were familiar with how an annuity works. Nearly two-thirds (63 percent) of those who are invested in a target-date fund expect that it will provide a guaranteed monthly paycheck for the length of their retirement. Most target-date funds, as of now, do not.

TIAA also said there is a lack of access to annuity products in employer-sponsored retirement plans. Only 32 percent of those surveyed had access to retirement plans with an annuity option. Among those who do not have access or are not sure if they have access to such products, half would like such an option.

Most of those surveyed support legislation to make it easier for employer retirement plans to include lifetime income products, such as annuities, as investment options (71 percent), and legislation that requires retirement account statements to include an estimate of monthly income in retirement (67 percent).

“The more you know about annuities, the better you can evaluate your options and select the investment products that best suit your financial needs and goals,” said Ron Pressman, chief executive officer of institutional financial services at TIAA.

While annuities can offer peace of mind to individuals by covering their fixed monthly expenses, people often draw upon other savings or supplemental income for discretionary spending. Most non-retirees surveyed plan to augment their retirement income with part-time work (52 percent) or full-time work (11 percent), which can provide extra income for travel, hobbies and other retirement activities, the survey said.