Most Americans fail to calculate how much money they will need for a steady and lasting retirement income, according to a new report.

MetLife Mature Market Institute, Westport, Conn., published this finding in a summary of results of a 2011 MetLife Retirement Income IQ, a quiz that includes 15 intelligence-quotient questions and 9 questions to address respondents’ retirement security and planning. The quiz was administered online in June by GfK North America to 1,213 pre-retirees, aged 56 to 65, who are working full-time and are within five years of retirement.

Of the total polled, the majority answered only five of the 15 questions correctly, leaving persistent misperception and misunderstanding in a number of core areas, such as life expectancy, inflation, retirement income/savings, long-term care insurance and to some extent Social Security, MetLife reports.

In the 2008 version of the study, most respondents correctly answered six of the 15 questions. The 2011 study also asked questions related to additional aspects of Americans’ post-retirement income needs.

An increased number of respondents say that Social Security and Medicare are more important compared with five years ago (45% in 2011 vs. 33% in 2008). And 45% of those surveyed said they are likely to work longer than previously planned.

However, only 17% knew that delaying the collection of Social Security by three years would add 24% to the amount they receive, MetLife says.

The respondents’ average estimate of what a couple would need in pre-retirement income to cover their essential living expenses (i.e., housing, food, health care, transportation, insurance and taxes) was 61%, very close to informal estimates that about 60% is needed to take care of the absolute basics. Yet, the biggest concern expressed was having enough retirement income to cover them.

Among the study’s additional findings:

  • Sixty-two percent of those surveyed in 2011 realize that the greatest financial risk facing retirees is longevity, compared with 56% in 2008 and 23% in 2003.
  • When asked about concerns during retirement, the number one answer was having enough income to cover essential expenses (32%), followed by the ability to afford health care (18%).
  • The majority (87%) of respondents have taken steps toward ensuring adequate income for retirement, such as increasing their contributions to retirement plans or extending their working years. Just under two-thirds (62%) of them are currently seeking financial product advice.