Americans who are ill-prepared for retirement may not understand how long people tend to live after leaving the workforce, according to a new study.

A TIAA Institute and the Global Financial Literacy Excellence Center (GFLEC) at the George Washington University School of Business (GWSB) found that just 35% of respondents correctly identified the lifespan from age 65.

The survey was completed by a sample of 3,503 U.S. adults, ages 18 and older in January, and was weighted to be nationally representative, according to TIAA Institute.

Participants were asked to identify the associated likelihood of 65-year-olds to live to an advanced age — tagged as age 90 — and the likelihood of dying relatively early.

Improving longevity literacy “can promote better retirement security and mitigate longevity risk,” said Surya Kolluri, head of the TIAA Institute, noting that retirement income security inherently involves planning and saving for an uncertain period of time. The research also confirms a link between high levels of longevity literacy and overall retirement readiness, according to study authors.

Poor longevity literacy is more pronounced among men, who study authors claim are 10 percentage points more likely to underestimate the average life span at retirement age.

Educational programs must be paired with financial literacy training, study authors said.

“It is important to focus on longevity literacy and how it can be improved because just like financial literacy it matters for retirement outcomes,” study authors said. “Initiatives to improve longevity literacy alongside financial literacy can promote retirement security.”