The top content management systems — from w3techs.com

Excerpt:

38% of the websites use none of the content management systems that we monitor.
WordPress is used by 39.7% of all the websites, that is a content management system market share of 64.1%.

From DSC:
Though I love WordPress and it continues to do well market share-wise…for people who want to get into blogging and/or who want to get their voice out there, I’m disappointed that WordPress has gone the way of web design and production (i.e., into major complexities). WordPress needs a WordPress-Lite version or an easier-to-use interface/theme/template section for beginners (or something along those lines).