Denmark, the 2016 winner, is second on the list of 155 countries, followed in order by Iceland, Switzerland and Finland. Canada is seventh, Israel is 11th, the United States fell from 13th in 2016 to 14th, and Germany ranks 16th.
Britain is listed as 19th, Russia is 49th and Ukraine is 132nd. The three countries at the bottom of the list are, in order, Tanzania, Burundi and the Central African Republic.
The index uses data from 2014-16 to compile the 2017 ranking of happiness, formally known as "life satisfaction."
Independent researchers used a combination of empirical data and subjective opinion about incomes, social support, healthy life expectancy, freedom of choice, generosity of governments and individuals, and perception of corruption to determine the ranking of happiness.
Employment, income inequality, national gross domestic product, lack of corruption in government, and business and social support are among other factors in the countries' scores.
The 188-page report notes that Norway, which was fourth on the list in 2016, leads the current list because of indicators measuring social happiness, including variables of social caring, freedom to make personal decisions, honesty and health.
China, in 79th place on in the World Happiness Report list, was 21st on the improvements list.
The report noted the decline in the United States' ranking came from a drop in four indicators - access to social support, fewer donations to charities and humanitarian organizations, and a perceived increase in corruption. ■
What to read next
More inside POST