Aside from periodical reports from Korea that provides a list of users in their region that has been banned, Blizzard does not typically like to reveal intimate details of account actions or reporting. The more information that is revealed about the reporting system or actions being issued gives dishonest players the knowledge and means to alter their behavior to avoid getting reported and still be disruptive in games.
That being said there have been recent developer video updates and dev posts that show rough figures on how much of an impact we have made ever since report notifications have been made and how much of an impact the endorsement system has made in our games.
