March 14 (UPI) -- Finland is the happiest place in the world to live, a ranking in a comprehensive annual United Nations report said Wednesday.
This year, Finland replaced Norway as the top nation listed in the 172-page World Happiness Report -- followed by Norway, Denmark, Iceland and Switzerland.
The Netherlands, Canada, New Zealand, Sweden and Australia round out the top 10.
The report, released ahead of the United Nations World Happiness Day on March 20, evaluated 156 countries and those at the top were found to have high values in six categories of well-being -- income, healthy life expectancy, social support, freedom, trust and generosity.
The United States fell from 14th to 18th this year, perhaps due to emerging health problems that threaten happiness -- obesity, the opioid crisis and depression. Those issues have been growing faster in the United States than in other countries, the report noted.
Other world powers on the list include Germany (at No. 15), Britain (19), Japan (54), Russia (59) and China (86).
The least happy country, according to the list, is Burundi -- as it leads a bottom 10 comprised mostly of African countries. Central African Republic ranked second-to-last, followed by South Sudan, Tanzania, Yemen, Rwanda, Syria, Liberia, Haiti and Malawi.
Togo was rated as the report's biggest gainer, moving up 17 spaces since 2015. The biggest loser is Venezuela, ranked at 102 and down 2.2 points on the "changes in happiness" scale.
The main focus of this year's report, in addition to its usual happiness factors, include migration within and among countries. The immigrant happiness rankings are based on Gallup data from 2005 to 2017, using 117 countries with more than 100 immigrant respondents.
"Perhaps the most striking finding of the whole report is that a ranking of countries according to the happiness of their immigrant populations is almost exactly the same as for the rest of the population," the report said. "The 10 happiest countries in the overall rankings also fill 10 of the top 11 spots in the ranking of immigrant happiness."
Norway was rated the world's happiest country in the 2017 report, followed by Denmark, Iceland and Switzerland. Finland was fifth a year ago.