Denmark has reclaimed its place as the world’s happiest country, while Burundi ranks as the least happy nation, according to the fourth World Happiness Report

The report, prepared by the Sustainable Development Solutions Network (SDSN) and the Earth Institute at Columbia University, showed Syria, Afghanistan and eight sub-Saharan countries as the 10 least happy places on earth to live.

Denmark topped the list in the first report, in 2012, and again in 2013, but it was displaced by Switzerland last year. In this year’s ranking, Denmark was back at No. 1, followed by Iceland, Norway, Finland, Canada, the Netherlands, New Zealand, Australia and Sweden.

The 2016 Happiness Report includes the rankings of 157 countries based on survey data from 2013 to 2015. Each country had an average sample size of 3,000 people who answered questions pertaining to six variables: gross domestic product (GDP) per capita, healthy life expectancy, social support, freedom, generosity and absence of corruption.

Denmark scored a happiness rating of 7.526 out of a possible 10 points, with Switzerland (7.509), Iceland (7.501) and Norway (7.498) close on its heels. The United States (7.104) placed 13th — up two spots from last year, when it ranked 15th out of 158 countries.

Of the world’s most populous nations, China came in at No. 83, India at No. 118, Indonesia at No. 79, Brazil at No. 17, Pakistan at No. 92, Nigeria at No. 103, Bangladesh at No. 110, Russia at No. 56, Japan at No. 53 and Mexico at No. 21.

Professor Jeffery Sachs, special advisor to U.N. Secretary-General Ban Ki-moon said, ‘There is a very strong message for my country, the United States, which is very rich, has gotten a lot richer over the last 50 years, but has gotten no happier.’

“The message for the United States is clear. For a society that just chases money, we are chasing the wrong things. Our social fabric is deteriorating, social trust is deteriorating, faith in government is deteriorating,” he added.

The bottom 10 was Madagascar, Tanzania, Liberia, Guinea, Rwanda, Benin, Afghanistan, Togo, Syria, and Burundi.