People in most countries around the world are happier these days, according to newly released data from the World Values Survey based at the University of Michigan Institute for Social Research.

Data from representative national surveys conducted from 1981 to 2007 show the happiness index rose in an overwhelming majority of nations studied.

"It's a surprising finding," said U-M political scientist Ronald Inglehart, who directs the World Values Surveys and is the lead author of an article on the topic to be published in the July 2008 issue of the journal Perspectives on Psychological Science. "It's widely believed that it's almost impossible to raise an entire country's happiness level."

The 2007 wave of 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.

During the past 26 years, the World Values Surveys have asked more than 350,000 people how happy they are, using the same two questions.

"Taking all things together, would you say you are very happy, rather happy, not very happy, not at all happy?" And, "All things considered, how satisfied are you with your life as a whole these days?"

Combining responses to these two questions, Inglehart and colleagues constructed an index of subjective well-being that reflects both happiness and general life satisfaction.

In the 52 countries for which a substantial time series is available (covering 17 years on average), this index rose in 40 countries and fell in only 12. The average percentage of people who said they were "very happy" increased by almost seven points.

"Most earlier research has suggested that happiness levels are stable," Inglehart said. "Important events like winning the lottery or learning you have cancer can lead to short-term changes, but in the long run most previous research suggests that people and nations are stuck on a 'hedonic treadmill.' The belief has been that no matter what happens or what we do, basic happiness levels are stable and don't really change."

The new findings from the World Values Surveys not only show that during the past 25 years, happiness has in fact risen substantially in most countries. Fully as important as the fact that happiness rose is the reason why. In recent decades, low-income countries such as India and China have experienced unprecedented rates of economic growth, dozens of medium-income countries have democratized and there has been a sharp rise of gender equality and tolerance of ethnic minorities and gays and lesbians in developed societies.

Economic growth, democratization and rising social tolerance have all contributed to rising happiness, with democratization and rising tolerance having even more impact than economic growth. All of these changes have contributed to providing people with a wider range of choice in how to live their lives---which is a key factor in happiness.

The people of rich countries tend to be happier than those of poor countries, but even controlling for economic factors, certain types of societies are much happier than others.

"The results clearly show that the happiest societies are those that allow people the freedom to choose how to live their lives," Inglehart said.

As an example, Inglehart points to the tolerant social norms and democratic political systems in Denmark, Iceland, Switzerland, the Netherlands and Canada all of which rank among the 10 happiest countries in the world.

"The events of the past 25 years have brought a growing sense of freedom that seems to be even more important than economic development in contributing to rising happiness," Inglehart said. "Moreover, the most effective way to maximize happiness seems to change with rising levels of economic development. In subsistence-level societies, happiness is closely linked with in-group solidarity, religiosity and national pride. At higher levels of economic security, free choice has the largest impact on happiness."

He also notes that the largest recent increases on the subjective well-being index, measuring both happiness and life-satisfaction, occurred in the Ukraine, followed by Moldova, Slovenia, Nigeria, Turkey and Russia.

"While most ex-communist countries show low levels of happiness, many of them show large recent increases in subjective well-being," Inglehart said. "The collapse of communism was generally followed by a sharp decline in well-being, which tended to rise again with economic recovery."