The majority of Linux distributions including Debian and Ubuntu have a GNU userland which is GPL licensed.

The notable exceptions are Android and some distributions and toolkits that target embedded systems such as OpenWRT

Linux without GNU is very far from a desktop Linux distribution experience that most users would recognize.

I don’t think counting distributions is the best metric. The majority of hamburger makers are individuals barbecuing at home, but McDonald’s dwarfs them.

Counting users, I guess Android has over 50% of them.

Counting installations (probably one of the fairer methods), I still would think Android has over 50% of Linux installations. Google gives me numbers in the million for the number of Google and Amazon servers, not always for recent years, but I guess they won’t have a hundred million servers combined.

(And of course, there’s the philosophical discussion whether Android is a Linux distribution, or something that uses a Linux)

There's also tons of embedded Linux devices, from your TV, your car, your fridge, home networking equipment... I don't know if theres enough of them to outweigh the massive number of phones in the world, but I think it's enough that Android wouldn't cross 50%, at least in north america.