https://www.techradar.com/news/cambridge-analytica-may-have-data-on-87-million-users-says-facebook

Facebook admitted today that Cambridge Analytica may have gained access to the private data of up to 87 million users, not the 50 million user figure that was previously reported. 

Chief Technology Officer Mike Schroepfer revealed the new figure in a blog post focused on Facebook's plans to “restrict data access” on the social media platform.