I was surprised to see this list from about one year ago showing Proton as the fifth largest email provider by number of users. Proton ranks below Yahoo, but above Zoho, GMX, and AOL. I wonder how many Gmail users are also iCloud and/or Outlook users? I know lots of people who have all three addresses.
#1 Gmail 1.5 billion
#2 iCloud 850 million
#3 Outlook 400 million
#4 Yahoo 230 million
#5 Proton 50 million
#6 Zoho 15 million
#7 GMX 11 million
#8 AOL 1.5 million
https://www.sellcell.com/blog/most-p...mber-of-users/