Imagine a ladder with 10 rungs. The top represents your best possible life. The bottom represents your worst possible life. Where does your actual life fall on the ladder?

That simple scenario and question — developed by social researcher Hadley Cantril — lies at the heart of the U.N. analysis, the 2016 update to its World Happiness Report released this month.

It found that Europe dominated the top 10 list of happiest countries, based on an analysis of Cantril ladder ratings collected by Gallup in 2013, 2014 and 2015 and totaling about 3,000 replies in each of more than 150 countries.

Europe was home to seven of the 10 countries whose residents reported the highest average life evaluations. The remaining three were Canada, New Zealand and Australia. The United States ranked 13th.