Norway is the world's happiest country, according to this year's World Happiness Report.
The Scandanvian country was ranked fourth last year, but has overtaken Denmark, Iceland and Switzerland to take the top spot on this year's list. Finland rounds out the top five.
Ireland is ranked 15 according to the report, which is put together by the United Nations Sustainable Development Solutions Network.
Ireland - up four places compared to 2016 - is just behind the US, but ahead of Germany, Belgium, Luxembourg and the UK.
The annual list is compiled by comparing and ranking a number of different factors - such as GDP per capita, healthy live expectancy, and the available social supports.
Explaining Norway's ascent to the top spot, the authors suggest: "It is sometimes said that Norway achieves and maintains its high happiness not because of its oil wealth, but in spite of it.
"By choosing to produce its oil slowly, and investing the proceeds for the future rather than spending them in the present, Norway has insulated itself from the boom and bust cycle of many other resource-rich economies."
They add: "To do this successfully requires high levels of mutual trust, shared purpose, generosity and good governance, all factors that help to keep Norway and other top countries where they are in the happiness rankings."
Maintaining happiness
Ireland and Iceland are cited as countries that managed to 'maintain happiness' despite the economic crash.
"Both suffered decimation of their banking systems as extreme as anywhere, and yet suffered incommensurately small happiness losses," the report suggests.
"That there is a continuing high degree of social support in both countries is indicated by the fact that of all the countries surveyed by the Gallup World Poll, the percentage of people who report that they have someone to count on in times of crisis remains highest in Iceland and very high in Ireland."
The world's 'least happiest' countries include a number of African countries - with Central African Republic, Burundi and Tanzania ranked lowest - while Syria is ranked 152nd of 155 countries.
In an analysis of African countries, the report notes: "Africa’s lower levels of happiness compared to other countries in the world, therefore, might be attributed to disappointment with different aspects of development under democracy."
However, it adds: "Although most countries in the world project that life circumstances will improve in future, Africa’s optimism may be exceptional. African people demonstrate ingenuity that makes life bearable even under less than perfect circumstances."
