The five happiest countries on Earth are Denmark, Norway, Switzerland, the Netherlands and Sweden. This despite the fact that they all experience cold, dark winters. All five countries are pretty much as happy as they were the last time the report was published.
The United States ranked as 17th-happiest country - slightly happier than the citizens of Ireland (No. 18) and a little less happy than Mexico (No. 16). Americans saw their overall happiness drop by about 3 percent over the five-year period between surveys.
Canadians are the sixth-happiest people in the world. Israelis came in at 11th, and the French rank 24th.
The unhappiest countries are the Central African Republic (No. 154), Benin (No. 155), and Togo (No. 156), which placed last.
The authors found that in general, happiness was up 7 percent in Latin America and the Caribbean, up 5.1 percent in East Asia and up 5.9 percent in the Commonwealth of Independent States (former Soviet republics). It was down 11.7 percent in the Middle East and North Africa and down 6.8 percent in South Asia.
To determine which countries are the happiest, the researchers asked an average of 3,000 people per country to rank their overall sense of life satisfaction on a scale of 1 to 10.
After analyzing tens of thousands of responses, the researchers identified six main dimensions to happiness, including income, mental and physical health, social support, freedom to make your own choices, being inclined to help others, and living under a government that doesn't seem corrupt.
"There is no one key to a society's well-being, but if you take these variables, they explain about three-quarters of the observed variation across countries," said Jeffrey Sachs, director of the Earth Institute at Columbia University and an author of the report.
He added that governments around the world have expressed great interest in the report.