A new study from The University of Southern California and Indiana University finds that up to 15% of active Twitter accounts are bots with built-in retweet and mention strategies that target specific groups. With 319 million monthly active users, that equates to roughly 48 million active bot accounts on Twitter, more than the population of California. This study is from March 2017. https://www.cbsnews.com/news/48-million-twitter-accounts-bots-university-of-southern-california-study/