the common good, which makes it central to Catholic social teaching," according to Bishop Marcelo Sanchez Sorondo, one of Pope Francis' key advisers at the Vatican.

Kaare Christensen, a university professor in demography and epidemiology in Odense, where fairy tale writer Hans Christian Andersen was born, says it doesn't take much to satisfy Danes.

"They are happy with what they get. Danes have no great expectations about what they do or what happens to them," she said

Christian Bjoernskov, an economy professor at the University of Aarhus, Denmark's second- largest city, believes feelings self-assurance and self-determination have a lot to do with it.

"Danes feel confident in one another... when we stand together we can succeed," he says. "And they also have a strong belief they can decide their own lives."

After Denmark,the next happiest nations last year were Switzerland, Iceland and Norway, followed by Finland, Canada, Netherlands, New Zealand, Australia and Sweden. The United States was 13th, two spots higher than the previous year.