Live expectancies continue to rise but that also means that more retirees are at risk of outliving their savings and having to rely only on benefits such as Social Security for their income, according to a GAO report.

“Despite the efforts by the federal government, plan sponsors, and others to encourage greater retirement savings, many individuals may not be adequately prepared for retirement,” said a recent GAO report.

It said that in retirement planning, it is common for individuals to underestimate their life expectancy and thus how long they will need to make their retirement savings last. In addition, many individuals will live beyond their personally projected life expectancy in any case, it said.

It added that life expectancy can be estimated from different initial ages, such as from birth or from some older age, but either way expectancy is increasing. For example, a 65-year-old man today on average will live to 86.1, up more than six years from a century ago, while for a 65-year-old woman it’s 88.8, up about five years.

Life expectancy varies by factors other than gender, it added. For example, various studies have shown that those at around the 25th percentile of earnings as they approach retirement have life expectancies of up to 13 years fewer than those at the 75th percentile. That is largely attributable to differences in health care received over a lifetime and the nature of their work.