The U.S. is no longer in the top 20 happiest countries in the world. It's the first time that's happened since rankings were started by Gallup back in 2012. Americans are now 23rd on the list of 140 nations. Happiness has fallen among all age groups, but particularly those under age 30, thanks in part to unaffordable housing and a growing sense of loneliness. The U.S. is still in the top 10 happiest countries for those 60 years old and above. Nordic countries top the list, with Finland at number one.