This measure of a country's happiness began in the year 2012, when the Sustainable Development Solutions Network (SDSN), a global initiative of the United Nations, gave the first report.
In this index, six factors are taken into account to check the status of different countries:
1. Gross Domestic Product (Income) per capita
2. Healthy Lifespan
3. Social Security (Whether there will be any help in trouble)
4. Trust (Govt. and general perception about corruption in private business)
5. Freedom (how free people feel to make decisions about their lives)
6. Generosity (recent donations).
Out of the above factors, social security, income and healthy lifespan, the difference between these three factors becomes the main basis for deciding the ranking of a country.