42% of all <i>websites</i> are on Wordpress, which is written in PHP.[a] The vast majority of those websites use vanilla WordPress out-of-the-box to serve a tiny audience.<p>If you look at market share by <i>traffic</i>, a much smaller share than 79% of the world's largest web sites (Wikipedia, YouTube, Google, Amazon, Facebook, Twitter, Reddit, Instagram, eBay, PornHub, etc.) run on PHP. Those websites account for the vast majority of Web traffic.<p>[a] Source: <a href="https://wordpress.com" rel="nofollow">https://wordpress.com</a><p>--<p>EDIT: I changed "0.0%" to "a much smaller share than 79%" because I was wrong about Wikipedia, Facebook, Pornhub and likely other high-traffic websites. See comments below.