https://www.google.com/intl/en/ipv6/statistics.html

Globally it’s at about 47% and growing at about 4% per year. If the rate remains unchanged it’ll be about a decade for >95%.

But the reality of it is, you don’t need global adoption out of the box. You just need majority adoption in the countries you visit, which for me are western countries (north America and Europe) which now have a majority adoption.