The World Happiness Report published this week ranked a country’s happiness overall and also by age for the first time since the inaugural list over a decade ago.

“The relationship between age and happiness is more nuanced than previously understood,” Ilana Ron Levey, Gallup’s managing director, tells Fortune in an email interview.

Researchers underscored a decline in happiness for Americans under 30 years old. It may help explain why the U.S. dropped out of the top 20 happiest countries for the first time, ranking 23rd compared to 15th a year prior. “The U.S. decline is at least partly attributable to Americans under age 30 feeling worse about their lives,” the report reads, released in partnership with Gallup, the Oxford Wellbeing Research Centre, and the UN Sustainable Development Solutions Network. 

For Americans over 60, the U.S. ranks in the top 10, but for those under 30, it drops to 62nd place. 

Levey hypothesizes the well-being differences may come down to the strength of people’s community and social ties. How people prioritize and interact with friends, family, coworkers, and others may differ depending on age. “We know that social support and loneliness affect happiness, and different generations have different levels of social connections,” she says. “Factors including school closures during COVID-19, technology use, and quality of friendships may affect the young and the old differently.” 

Levey hopes the report sheds light on the importance of combating loneliness, especially as long-standing research finds that the strength of people’s social connections throughout their lives determines the level of their happiness in old age. 

And more, securing deeper connections is something people can work at. 

“Happiness as you get older is based on many of the same factors as happiness when you are young,” Levey says. “Fostering strong social connections, helping others and demonstrating benevolence, and feeling like you have someone to count on in a time of need is crucial for happy aging, just like it is crucial at all ages.” 

Across the globe, younger people (between ages 15 and 24) were typically happier than older people, except for in North America.

“There is a great variety among countries in the relative happiness of the younger, older, and in-between populations,” says John F. Helliwell, founding editor of the World Happiness Report, in a press release. “Hence the global happiness rankings are quite different for the young and the old, to an extent that has changed a lot over the last dozen years.”

The rankings compile self-reported happiness responses on a scale of 0 to 10 from the Gallup World Poll’s sample between 2021 and 2023. Beyond the happiness rankings, the report also factors a country’s GDP, life expectancy, and people’s sense of freedom and corruption to shed light on individual nations’ needs.

Happiest countries in the world

1. Finland
2. Denmark
3. Iceland
4. Sweden
5. Israel
6. Netherlands
7. Norway
8. Luxembourg
9. Switzerland
10. Australia

Happiest countries in the world for the young and old

Happiest countries for those under age 30:

1. Lithuania
2. Israel
3. Serbia
4. Iceland
5. Denmark
6. Luxembourg
7. Finland
8. Romania
9. Netherlands
10. Czech Republic

Happiest countries for those 60 and older:

1. Denmark
2. Finland
3. Norway
4. Sweden
5. Iceland
6. New Zealand
7. Netherlands
8. Canada
9. Australia
10. United States