Along those lines, the survey also found that the number of Americans who aren't saving at all toward retirement is growing: in 2014, 21 percent said they weren't saving, while now that number has jumped to 29 percent. This despite the fact that 46 percent are afraid they'll run out of money in retirement.

Just 38 percent said they'd analyzed how their savings translates to monthly income once they retire, and quite a few of those had figured it out without resorting to consulting a financial professional. Instead, they did it themselves (18 percent) or looked elsewhere for help: 14 percent asked a friend or family member to figure it out, while 6 percent asked a coworker or a manager.

And that's probably why so few know anything about annuities. Even though 49 percent said that they'd willingly put part of their savings into a monthly income vehicle, such as an annuity, only 34 percent are even familiar with annuities. Just 29 percent have bought one or are planning to, and 28 percent regard them favorably.

The younger they are, the less they know about annuities, too. Although Americans between the ages of 18 and 34 feel, as does the general population, that a guaranteed source of monthly income in retirement is a priority (84 percent, the same as Americans overall), just 26 percent are familiar with annuities.

Older Americans are more likely to be acquainted with them; for instance, 48 percent of those 55-64 are familiar with them.