According to technology survey firm W3Techs, the content management platform (sometimes referred to as experience management) now powers upwards of 30 percent of websites – a 5 percent increase in the past two and a half years. That’s a significant increase in the past few years and it indicates not just the popularity of the system but the increased usage of such systems in general. What is really important here is that the data point relates to the entire Web, however, and not just those whose website uses a CMS

Source: WordPress Dominates the CMS Space