The United States fell to its lowest happiness ranking ever partly due to a rise in the number of Americans eating their meals alone, an annual UN-sponsored report said on Thursday.

Finland ranked as the world's happiest country for the eighth straight year in the World Happiness Report, with locals and experts thanking its grand lakes and strong welfare system for boosting its mood.

Afghanistan, plagued by a humanitarian catastrophe since the Taliban regained control in 2020, once again ranked as the unhappiest country in the world.

The United States fell to 24th place, its lowest score since the report was first published in 2012, when it recorded its highest showing at number 11.

"The number of people dining alone in the United States has increased 53 percent over the past two decades," the authors said, noting that sharing meals "is strongly linked with well-being."

In 2023, roughly one in four Americans reported eating all their meals alone the previous day, the report said.

"The increasing number of people who eat alone is one reason for declining well-being in the United States," it said.

It also noted that the United States was one of few countries to see a rise of so-called "deaths of despair" – from suicide or substance abuse – at a time when those deaths are declining in a majority of countries.

The report surveyed people worldwide in 2022-2024, before US President Donald Trump's shakeup of national and global affairs since returning to the White House in January.

Nordic countries all stayed among the 10 happiest, with Denmark, Iceland and Sweden trailing Finland, which slightly extended its lead over runner-up Denmark.

Meanwhile, Costa Rica and Mexico entered the top 10 for the first time, at the sixth and 10th spot respectively.

The happiness ranking is based on a three-year average of individuals' self-assessed evaluations of life satisfaction, as well as GDP per capita, social support, healthy life expectancy, freedom, generosity and corruption. (AFP)