Denmark has been ranked as the 'happiest nation' by the United Nations' World Happiness Report 2013.
According to the report, while Denmark topped the list, African nation of Togo ranked last on the happiness quotient.
Director of the Earth Institute at Columbia University, Director of the SDSN, Professor Jeffrey D. Sachs said that the UN report offers rich evidence that the systematic measurement and analysis of happiness can teach a lot about ways to improve the world's well-being and sustainable development, the New York Daily News reports.
The researchers asked an average of 3,000 residents of each country to rank their life satisfaction and identified major categories of happiness that included income, health, social support, and freedom.
Meanwhile, residents of African nations like Central African Republic and Benin ranked at the bottom of the happiness survey while the US came 17th less happy than Canada, with a drop of three percent over the past five years.
Middle East residents' happiness quotient dropped 11.7 percent overall, the report added.