Cloudflare sees over 40%, and it hasn't gone up in the last year even with the overall traffic increase. Personally, as the APNIC article also says about their own observations, I guess the overall adoption is somewhere in between.

https://radar.cloudflare.com/adoption-and-usage#ipv4-vs-ipv6

But we have to remember that this reflects the adoption on the client side. With many high profile services still IPv4-only, the fraction of IPv6 flowing on the public Internet might be much lower.

I wonder what incentives are needed to push this forward, because it's not the same incentives as years ago for sure. We've long since exhausted new IPv4 allocations.