No OECD nation (outside the USA) has a drinking age that high. We might, perhaps look at other reasons why alcohol remains a large problem here (inequality, stress at work, a prudish culture that binges, etc.). Also see the national comparisons. almost now one has one over 18 years of age. https://en.wikipedia.org/wiki/Legal_drinking_age

At the age of 20, NZ would be relegated as one of the most prudish nations in the world outside of the USA, Tonga and a handful of Muslim nations (where alcohol is permitted but frowned upon by the religion). No OECD nation has the drinking age that high. We might, perhaps look at other reasons why alcohol remains a large problem here (inequality, stress at work, a prudish culture that binges, etc.).