To determine just who are the happiest people in the world, researchers at the Gallup World Poll surveyed thousands of respondents in 155 countries between 2005 and 2009 and found that “by and large, rich countries are happier.”

According to their poll, the five happiest countries in the world are Denmark, Finland, Norway, Sweden and the Netherlands. All are clustered in the same region, and all enjoy high levels of prosperity.

Costa Rica and New Zealand tie for sixth place, with Israel, Canada, Australia and Switzerland sharing eighth.

Subjects were first asked to reflect on their overall satisfaction with their lives, and their answers were ranked using a “life evaluation” score from one to 10.

Then they were asked questions about how they had felt the previous day. The answers allowed researchers to score the subjects’ “daily experiences” – things like whether they felt well-rested, respected, pain-free and intellectually engaged.

Subjects reporting high scores were considered “thriving.” The percentage of thriving individuals in each country determined the rankings.

Jim Harter, a chief scientist at Gallup, which developed the poll, says, “One theory why [people are happier in the country’s that top the list] is that they have their basic needs taken care of to a higher degree than other countries…”