I've got it at 38.32%. I'm looking at the 'front-door' of the web, active sites, no subdomains, from Crux user experience data.

Will be publishing a report on www.theweb.report soon - if you're interested.

That's a seed of about 13 million domains - pretty sure WordPress would be dominating the even longer tail.

( Also worth noting it's sooo easy to detect a site is WordPress, it screams it across every signal we gather, where-as some sites are just well made and have limited information leaks ).