In my previous blog entry, I said I would research the Nordic Model. The gist of it is that the Scandinavian nations use very high income taxes to provide cradle-to-grave welfare services. On the whole, this makes their citizens happier than those in most other nations.
I was going to say more about this but it seems less relevant now that I see that populations of these happy nations, plus many others, are dwindling. Regardless of their other quality of life metrics, it appears that whatever they are doing is unsustainable. For guidance, we need to examine the policies of those few nations that are both happy and growing.
Click on one of the following images to zoom in on the fertility versus happiness data plots that I created by combining data from Wikipedia. The first two plots show the same data points but with the axes flipped. The third is a labeled close-up of the happiest nations with those in decline on the left and those that are thriving on the right.