Norway claimed the No. 1 spot as the world's happiest country, according to a United Nations report, which described the United States as "a story of reduced happiness."
The Scandinavian country was shadowed by Nordic neighbours Denmark and Iceland, as well as Switzerland, in the World Happiness Report released on Monday.
The top four countries scored high on factors that are key to happiness such as "caring, freedom, generosity, honesty, health, income and good governance," according to the report.
Last year, Denmark claimed the top spot.
Rounding off the list of the top 10 happiest countries were Finland, the Netherlands, Canada, New Zealand, Australia, and Sweden.
Oil and gas-rich Norway was cited as having managed "to produce its oil slowly, and investing the proceeds for the future rather than spending them in the present."
Norway has thereby avoided "the boom and bust cycle of many other resource-rich economies," the report said.
The United States was ranked 14th. 
In 2007, the US was ranked third among Organisation for Economic Co-operation and Development (OECD) countries, and it came in at 19th place in 2016, the report said, citing "declining social support and increased corruption" as factors.
Trailing the World Happiness list were Rwanda, Burundi, Tanzania and the Central African Republic.
The report was released in New York in conjunction with the World Happiness Day.
The list has been used by the UN since 2012 when Bhutan secured support for a proposal to recognise happiness as a universal goal and as a guiding principle for public policies.

World's 10 happiest and saddest countries

The following are the top 10 countries in terms of happiness and the 10 most unhappy as listed by the United Nations in the World Happiness Report 2017.
The use of happiness has gained ground in the UN as it is viewed to be "the proper measure of social progress and the goal of public policy."
The report combines six factors for its rating: GDP per capita, healthy years of life expectancy, social support (having someone to rely on during hard times), absence of corruption in government and business), social freedom, and generosity (measured by recent donations).

The 10 most happy:

1. Norway

2. Denmark

3. Iceland

4. Switzerland

5. Finland

6. The Netherlands

7. Canada

8. New Zealand

9. Australia

10. Sweden

The 10 most unhappy:

146. Yemen

147. South Sudan

148. Liberia

149. Guinea

150. Togo

151. Rwanda

152. Syria

153. Tanzania

154. Burundi

155. Central African Republic