The happiest countries in the world are all in Northern Europe (Denmark, Norway, Finland, Netherlands). Their average life evaluation score is 7.6 on a 0-to-10 scale. The least happy countries are all poor countries in Sub-Saharan Africa (Togo, Benin, Central African Republic, Sierra Leone) with average life evaluation scores of 3.4. But it is not just wealth that makes people happy: Political freedom, strong social networks and an absence of corruption are together more important than income in explaining well-being differences between the top and bottom countries. At the individual level, good mental and physical health, someone to count on, job security and stable families are crucial.
Read more on website of the Earth Institute at Colombia University