FINLAND has been named the world's happiest country for the fifth year running, in an annual UN-sponsored index that again ranked Afghanistan as the unhappiest, followed closely by Lebanon.

Serbia, Bulgaria and Romania recorded the biggest boosts in wellbeing. The largest falls in the World Happiness table, released on Friday, came in Lebanon, Venezuela and Afghanistan.

Lebanon, which is facing economic meltdown, fell to second from last on the index of 146 nations, just below Zimbabwe.

War-traumatised Afghanistan, already bottom of the table, has seen its humanitarian crisis deepen since the Taliban took power again last August.

UN agency UNICEF estimates one million children under five could die of hunger this winter if not aided.

"This (index) presents a stark reminder of the material and immaterial damage that war does to its many victims," co-author Jan-Emmanuel De Neve said.

The World Happiness Report, now in its 10th year, is based on people's own assessment of their happiness, as well as economic and social data.

It assigns a happiness score on a scale of zero to 10, based on an average of data over a three-year period. This latest edition was completed before the Russian invasion of Ukraine.

Northern Europeans once again dominated the top spots -- with the Danes second behind the Finns, followed by the Icelandic, the Swiss and the Dutch.

The United States rose three places to 16th, one ahead of Britain, while France climbed to 20th, its highest ranking yet.

As well as a personal sense of wellbeing, based on Gallup polls in each country, the happiness score takes account of GDP, social support, personal freedom and levels of corruption.

This year the authors also used data from social media to compare people's emotions before and after the Covid-19 pandemic. They found "strong increases in anxiety and sadness" in 18 countries but a fall in feelings of anger.

"The lesson of the World Happiness Report over the years is that social support, generosity to one another and honesty in government are crucial for wellbeing," report co-author Jeffrey Sachs wrote.

"World leaders should take heed."

The report raised some eyebrows when it first placed Finland at the top of its listings in 2018.

Many of the Nordic country's 5.5 million people describe themselves as taciturn and prone to melancholy, and admit to eyeing public displays of joyfulness with suspicion. 

But the country of vast forests and lakes is also known for its well-functioning public services, ubiquitous saunas, widespread trust in authority and low levels of crime and inequality.