That doesn't tell you how many different engines there are that support it though, only the amount of marketshare covered. Compare it to web-bluetooth (which both Apple and Mozilla have rejected and is hence not a standard): https://caniuse.com/web-bluetooth, which shows 76.24% (as of this post's time). Chromium-based broswers have it, others do not, hence it doesn't really matter what the actual percentage is, only which engines support it (and currently, of the big 3, only 1 does support it).
