(Warning: useless political data geekery below.)

Today, former president Jimmy Carter has reached a milestone: he is now the longest-retired president in U.S. history. In other words, he has lived longer after leaving the presidency than any other U.S. president. He has been “ex-president Jimmy Carter” for 11,554 days: that’s about 31 years and 7 1/2 months.

How long has he been an ex-president? When Jimmy Carter left office on January 20, 1981, there was no MTV. There was no IBM PC. Lady Diana Spencer was not yet the Princess of Wales. Nobody had heard of AIDS. Since Carter left office, children have been born and have grown up to have children of their own. The Reagan era, the Clinton era, and two Bushes have come and gone.

Previously, the longest-retired president was Herbert Hoover. Hoover left office on March 4, 1933, and on July 5, 1958, he became the longest-retired president in U.S. history, surpassing John Adams. Hoover died on October 20, 1964, having lived 11,553 days as an ex-president:

Yesterday, Carter tied Hoover’s record, and today he surpasses it.

The day after Carter left office — after a quick stop home in Plains, Georgia — he flew to Germany to greet the just-released Iranian hostages.

Four days ago, he spoke via video to the Democratic National Convention to endorse President Obama’s re-election.

It’s been a long ex-presidency. He turns 88 in a few weeks. Longer may he live.