True, they are one of the riches countries, but I think if we talk about adoption, isn't total number of user better than total amount?
It is theoretically possible that in a country like Switzerland there are more people who use/own Bitcoin than in a country with perhaps ten times as many inhabitants. Even at least 5+ years ago in Switzerland, you could buy Bitcoin at a machine where train tickets are sold, or you could pay taxes in the same in some of their cities.
I want to say that in some countries financial literacy is much higher than in others, and this combined with favorable regulation creates a positive environment in which people are not afraid to invest in Bitcoin as in some other countries in Europe where the central banks practically call it a fraud.
When we talk about the total number of users, or perhaps it is better to say those who own Bitcoin, some studies say that this number is somewhere around 2% of the total population, while the most optimistic ones go up to 5%. In any case, this is definitely too little considering that Bitcoin has existed since 2009.
