I know I'm showing my age here, but I still think that the answer to this question should be "none". I still think that if your website or web application doesn't work without JS, then you've made a mistake in either your design or implementation. Worse, you're making unwarranted assumptions about what sort of hardware, software, and connection they're using. This is not to say that you must not use JavaScript, but when I see that a site isn't using JS for progressive enhancement, but is instead JS-dependent, then I assume that the developers are up to something nefarious.