I guess it depends on how you look at it, since AI tooling can generate so much code. There are a lot of project on GitHub that are heavy on AI tooling use but are they really being used? If we count them, that does inflate the amount of total code in existence.

In terms of code out there, in the world doing actual work, I'm skeptical that the amount of AI generated code is as high as 90%. In terms of model generating production code without human interaction (i.e. wholly replacing the software developer) I think we've fallen far short of his prediction.