83% WordPress usage among CMS users seems high, but 22% using a CMS at all seems low. Presumably most using a CMS just want a blog and a few pages? Any kind of complicated content structure goes straight to custom development? Does this account for static generators like Jekyll or CMSes that don't provide information about themselves?
I would think that many of them don't expose plainly the fact that they're powered by WordPress or only use it as a backend/authoring solution with a custom frontend.
Might be because often the standard content pages are a small part of many startup sites so they just tack something custom onto their site build rather than use a full CMS.
