Most Americans underestimate needed retirement income

"In addition to unrealistic expectations about the amount they will need to live on, Americans are unclear about how much they need to save," the report states. "Experts recommend that Americans save at least 10 percent of their annual income for retirement, including contributions from their employers.

"However, the TIAA-CREF survey found that 44 percent of those who haven't retired are saving 10 percent or less of their annual income," the report adds. "Even more alarming is that 21 percent aren't saving for retirement at all."

Forty-four percent of survey respondents are somewhat concerned (20 percent) or very concerned (24 percent) they may run out of money in retirement. But just 21 percent expect to receive income from annuities.

Fifty-three percent plan to use savings withdrawals as one of the sources of monthly retirement income, yet TIAA-CREF research shows that if retirees make withdrawals from their retirement savings that are equal to the income payments they would receive from a lifetime annuity (assuming the same interest rate), there is a greater than 50 percent chance that the retiree will outlive his or her savings — whereas the annuity payments continue for as long as the retiree lives.