WPMU have reported in a recent article that yes, a fifth of the world's websites are powered by WordPress.
The news comes form W3Tech's Content Management Systems Survey, which reports that WordPress is now used by 19.9% of all websites. At the start of the year on 1st January it was at 17.4%, which means it has made a leap of 2.5% in just nine months.
The survey shows WordPress to be by far the most popular CMS out there, with its competitors paling in comparison. Joomla is used by 3.3% of websites, Drupal used by 2% and Blogger, at the lowest, is used by just 1.2% of all websites.
Other good news for WordPress this week was that WordPress.com's monthly visits outranked web-giants Yahoo and Yelp in Quantcast's Top Sites ranking, becoming the 8th most visited site in the US. This is a huge 45% increase over the last year, which means WordPress has moved up a whopping 12 places in ranking. Quantcast's figures are made on the number of people in the US who visit each site ieach month. WordPress clocked up 73 million hits, while Yahoo reached just under 70 million and Yelp just over 66 million. Google, of course, came in top with 195 million monthly visits.