The Nordic countries might look similar to each other from the outside but in fact they often differ substantially.
In Norway (about 9% of the population [1]) at least it appears to be similar to the UK (about 13% or respondents to a survey[2])
So I'm not sure if that counts as very common and in Norway it is largely a perk offered by companies as part of the salary package rather than something that individuals choose for themselves.
On the other hand Denmark has about twice as many people with private health insurance [1] as Norway and about the same population.
In Norway (about 9% of the population [1]) at least it appears to be similar to the UK (about 13% or respondents to a survey[2])
So I'm not sure if that counts as very common and in Norway it is largely a perk offered by companies as part of the salary package rather than something that individuals choose for themselves.
On the other hand Denmark has about twice as many people with private health insurance [1] as Norway and about the same population.
[1] https://www.nrk.no/norge/nesten-en-halv-million-nordmenn-har...
[2] https://www.finder.com/uk/health-insurance-statistics