(Newser) – Jimmy Carter has already lived longer after leaving office than any other president—more than 38 years. And on Friday, he'll be 94 years and 172 days old, the Journal Constitution reports, passing the record set by George HW Bush as the oldest living former president. Carter has kept busy since leaving office at age 56: He's written more than two dozen books, built Habitat for Humanity houses, won a Nobel Peace Prize, and established the Carter Center in Atlanta. Asked about their longevity, a Carter Center spokesperson told CNN that the former president and his wife, Rosalynn, 91, "take walks, and they have followed a healthy diet for a lifetime." They have no plans to stop their work, she said: "President and Mrs. Carter are both determined to use their influence for as long as they can to make the world a better place." (Carter has spoken out about the current president's decisions.)