Complex sentence: As of February 2017, WordPress is used by 58.7% of all the websites whose content management system is known by w3techs; this is 27.5% of the top 10 million websites.
Split into simpler sentences: As of February 2017, WordPress is used by 58.7% of all the websites whose content management system we know. This is 27.5% of the top 10 million websites.