Terry Chay has posted the answer to an interesting question about the PHP language that asks what is something very few know about PHP. The original answer was shared on Quora but he's copied it here for more visibility.

Question: What’s something very few people know about PHP? Answer: It is mind-bogglingly popular for web development. That popularity hasn’t diminished even though conventional wisdom says otherwise…

Over a decade ago, I said about 40% of the top 100 websites use PHP. [...] Overall, almost 80% of the internet is powered by PHP, and that has held steady for years! Newer web languages such as Ruby or NodeJS have only grown at the expense of other languages such as ASP, Java, or Perl.

He also shares some about the role of WordPress in these numbers (a big chunk at 30%) and a guess at how many PHP developers there are in the world right now.