[mh-]

This would be woefully inaccurate for websites with a large amount of mobile traffic (because of CGNAT), or university traffic, or etc.

[icefo]

Don't universities have a huge number of IPs because they were the first to use internet ?

Mine gives one public ipv4 per device that access the internet on the network (with some exceptions). Strategies varies but if you have a lot of addresses why not use them.

[jannes]

That might be true for some US universities, but it's definitely not true for the rest of the world.

[BlueTemplar]

According to Google, IPv6 traffic is up to 30% these days.