When you actually have a real source or numbers, let me know.
Sometimes people speak in broad generalities, or use "Internet" when they mean "Web." It is in fact extraordinarily common.
It's also wrong.
http://w3techs.com/technologies/details/pl-php/all/all
No matter how you try to hide from it, it's blatantly clear that PHP runs at least half the entire Web.
What else exactly did you think was? Surely you didn't think Python was running half the web. Obviously Ruby isn't. So what does that leave? Coldfusion? C?
Well, in principle, there's no reason any one language has to run half the web by itself. And there are also static pages.
Of course, once actual evidence is involved, this is just an adventure in nitpicking.