The latest wave of World Values Surveys shows happiness has increased worldwide from 1981 to 2007. The surveys also provides a ranking of 97 nations containing 90 percent of the world's population. The results indicate that Denmark is the happiest nation in the world and Zimbabwe the unhappiest. The United States ranks 16th on the list, immediately after New Zealand. The World Values Survey (WVS) is the work of a global network of social scientists who perform periodic surveys addressing a number of issues. The latest surveys, taken in the United States and in several developing countries, showed increased happiness from 1981 to 2007 in 45 of 52 countries for which substantial time series data was available.
Researchers responsible for the analysis, from the University of Michigan's Institute for Social Research (ISR) in Ann Arbor, say the overall rise in reported happiness is due to greater economic growth, democratization and social tolerance.
Denmark tops the list of surveyed nations, along with Puerto Rico and Colombia.
A dozen other countries, including Ireland, Switzerland, the Netherlands, Canada and Sweden also rank above the United States, which maintains about the same relative position as it did in WVS's 2000 survey.
Researchers measured happiness by simply asking people how happy they were, and how satisfied they were with their lives as a whole.
Ninety-seven percent of respondents - an exceptionally high response rate - gave answers that strongly correlated with how satisfied they were with various aspects of life such as gender equality and tolerance of minorities.
Interestingly, countries whose respondents reported high levels of happiness were much likelier to be democracies than were countries that rank lower in terms of their citizens' happiness.
Three of the world's poorer countries with long histories of repressive government - Moldova, Armenia and Zimbabwe - are at the bottom of the happiness list. Virtually all of the lowest ranking nations struggle with legacies of authoritarian rule and widespread poverty.
The World Values Survey has measured happiness since 1981. Its researchers have interviewed more than 350,000 people.