The Nordic nations are the most content, according to the World Happiness Report 2017 produced by the Sustainable Development Solutions Network (SDSN), a global initiative launched by the United Nations in 2012.
Countries in sub-Saharan Africa, along with Syria and Yemen, are the least happy of the 155 countries ranked in the fifth annual report released at the United Nations.
"Happy countries are the ones that have a healthy balance of prosperity, as conventionally measured, and social capital, meaning a high degree of trust in a society, low inequality and confidence in government," Jeffrey Sachs, the director of the SDSN and a special advisor to the United Nations Secretary-General, said in an interview with Reuters.
The aim of the report, he added, is to provide another tool for governments, business and civil society to help their countries find a better way to wellbeing.
Denmark, Iceland, Switzerland, Finland, Netherlands, Canada, New Zealand, Australia and Sweden rounded out the top ten countries.
South Sudan, Liberia, Guinea, Togo, Rwanda, Tanzania, Burundi and the Central African Republic were at the bottom.
Germany was ranked 16, followed by the United Kingdom (19) and France (31). The United States dropped one spot to 14.
Croatia was ranked 77, three places down from last year and 15 places down from 2015.
Of the neighbouring countries, Italy was ranked 48, Slovenia 62, Serbia 73, Hungary 75, Montenegro 83 and Bosnia and Herzegovina 90.
The rankings are based on six factors -- per capita gross domestic product, healthy life expectancy, freedom, generosity, social support and absence of corruption in government or business.