Is it Buddhism? IS IT BUDDHISM? Noooo. Buddhism makes people just slightly happier than other non-western beliefs. As we’ve seen before the influence of Human Development on this score is too significant, so a mere way of thinking does not overcome people’s general attitudes towards their life as strongly as material provisions do.

What: Average happiness score from World Happiness Report by belief. It was calculated only for those countries where followers of a particular belief make more than 10% of the population and it was weighted by that percentage. Judaism and “other beliefs” were excluded because they had only 1 country complying with such criteria. It was Israel for Judaism and Taiwan for “other beliefs”. I guess that “belief” was Taoism.
When: 2019 for happiness, 2020 for religion (it’s an estimate) because the latest actual data were of 2010.
Where: 155 countries of the world.
Source: WHR and Pew Research Center