At their Q3 FY19 earnings call, Microsoft CEO Satya Nadella said that Office 365 is now used by 180 million monthly active users. Office 365 is now growing at more than 4 million users per month. The earnings call also noted success for Enterprise Mobility and Security and the Outlook mobile client, both of which are now used by more than 100 million people.
https://office365itpros.com/2019/04/25/office-365-reaches-180-million-users/
