Open Source Content Management System Market Share
http://www.waterandstone.com/downloads/2008OpenSourceCMSMarketSurvey.pdf

Shreves, Ric
Water and Stone
2008

Abstract:

The survey shows that three systems have come to dominate the present market: WordPress, Joomla! and Drupal. Indeed, the numbers indicate that these three systems have opened up a large lead on the rest of the pack and have emerged as the dominant brands in the market.