Asking an annoyed rhetorical question doesn't seem productive to the point you're trying to make here.

As an actual answer, it would be variable proportional to the size of the window between releases mentioned here: https://en.wikipedia.org/wiki/JQuery#Release_history

I'm sure a fair amount of people serve jQuery from a local storage. The usefulness that the user might already have it cached is a non-zero point, no matter how insignificant you may think it is.