U.S. President Joe Biden is considering a reelection bid for a second term in office in 2024. Biden is already the oldest American president to become president, taking office at the age of 78. He's also the only president to turn 80 while in office, and the ninth oldest national leader in the world, according to a new Pew Research Center analysis. 

Former U.S. President Donald Trump is running to hold the office again in 2024, and at age 76, is younger than Biden, but according to the Pew analysis, he would still rank among the 25 oldest world leaders. 

Let’s take a look at five key facts presented by the Pew Research Center on the ages of national leaders. 

National leaders span in age from their mid-30s to 90.

Gabriel Boric, the president of Chile, is currently the youngest national leader at age 37. However, the interim leader of Burkina Faso in West Africa, Ibrahim Traoré, is believed to be younger than Boric but was not part of the analysis as his exact birth date is unknown.

Other national leaders in their 30s include Sanna Marin of Finland and Dritan Abazović of Montenegro, both 37 years old. At the other end, the oldest national leader is Paul Biya, president of Cameroon in Central Africa, who is 90 years old and has been in office for more than 40 years. 

Current global leaders have a median age of 62, and when broken down by decade.

The highest percentage (35%) are in their 60s. 22% of leaders are in their 50s, while 18% each are in their 40s or 70s. Biden is among the 5% of leaders in their 80s.

National leaders in countries that are less free tend to be older. 

In countries that the non-profit civil liberties group Freedom House classifies as "not free," the median age of leaders is 69, while it is 61 in "partly free" countries and 58 in "free" countries. 

It is noteworthy that the United States and Namibia are the only two countries classified as "free" that have leaders age 80 or older, with the President of Namibia, Hage Geingob, being 81 years old.

Women leaders are typically younger than their male counterparts.

Although there are only 13 countries with a female leader in the top office, their median age is 57, compared to 62 for male national leaders. 

Sanna Marin, the Prime Minister of Finland, is currently the youngest woman in power at 37 years old, having been sworn in at age 34. 

Five other women leaders are in their 40s, including Mette Frederiksen of Denmark, Kaja Kallas of Estonia, Katrín Jakobsdóttir of Iceland, Giorgia Meloni of Italy, and Ana Brnabić of Serbia.

Leaders in most countries are significantly older than the median member of the population.

While the median age of an American citizen is 38, Biden is more than twice as old. Only four countries, namely Andorra, Montenegro, Italy, and Finland, have leaders who are younger than their median resident.

Overall, countries that are classified as "free" by Freedom House are more likely to have leaders who are closer in age to their median resident than those classified as "partly free" or "not free."

For more, check out our exclusive content on CGTN Now and subscribe to our weekly newsletter, The China Report.