Two of the leading 2020 Democratic presidential candidates, former Vice President Joe Biden and Vermont Sen. Bernie Sanders, will be inching toward their 80th birthdays come Election Day.

Though Biden and Sanders are polling well among Democratic voters, their success belies what voters told the Pew Research Center in a new poll on how they see the age of candidates.

[ANALYSIS: Age, change and the Democrats’ challenge]

Pew, a nonpartisan arm of The Pew Charitable Trusts that conducts research and polls, found that the age of presidential candidates is important to potential Democratic or Democratic-leaning voters and that they prefer their candidates younger, specifically in their 40s, 50s and 60s.

The Pew survey, conducted early last month, found that 47 percent of Democratic voters say the best age for presidents is their 50s. If he were to win next year, Biden would be 78 upon taking office in 2021. Sanders would be 79.