I have no answer to that. But I can answer why Finland has a high rate. Mobile connections have IPv6 like in most countries. For fixed ones it's impossible to g

I have no answer to that. But I can answer why Finland has a high rate. Mobile connections have IPv6 like in most countries. For fixed ones it's impossible to get for consumer subscriptions. But here fixed networks are being actively shut down. Mobile connections are cheaper and faster. (That does not hold for fiber, but fiber is still not widely available. And with the dominance of mobile I am not sure that this will change quickly.)