If we take the total number of computer users globally, and look at who use GUI vs CLI, the latter will be a teeny tiny fraction.
But most of those will likely be developers, that use the CLI in a very particular way.
If we now subdivide further, and look at the people that use the CLI for things like browsing the web, that's going to be an even smaller number of people. Negligible, in the big picture.
Don't forget to count people that require screen readers, this is often a less vocal minority that often depend on CLI tools for interaction with the computer.
But most of those will likely be developers, that use the CLI in a very particular way.
If we now subdivide further, and look at the people that use the CLI for things like browsing the web, that's going to be an even smaller number of people. Negligible, in the big picture.