Analyzing the Numbers for Different Office 365 Workloads

Microsoft says that Office 365 has 155 million monthly active users. That's an interesting statistic, but how many people use Exchange, SharePoint, Teams, Yammer, and Planner? Microsoft never gives firm numbers, only clues to what might be happening, so we have to do some analysis to tease out what might be happening behind the Office 365 curtain.
https://www.petri.com/analyzing-numbers-different-office-365-workloads