I don't have an answer to your question but I do have a couple of questions about that map.

Firstly Monaco, the Mediterranean Principality famous for it's F1 track, super-yachts and multi-millionaires, has among the lowest wealth per adult in western Europe?! Only Spain, Portugal and Malta have lower wealth per capita. I'm gonna press X on that.

Secondly Cyprus has a wealth per adult of 35%. What does that even mean?