Great article in the Guardian written by Dr. Monica Seeley (published 6th Nov 2017).
Dr Monica Seeley is the author of Brilliant Email and Taking Control of Your Inbox – and her latest article says, “About 269bn emails are sent a day, according to data from the Radicati Group, which means almost 2.4m emails are sent every second. So it’s hardly surprising that email overload is now a major cause of stress and disruption. People either feel they can never completely disconnect, or find they are drowning in torrents of new emails if they do manage to take time to switch off.”
The full article can be seen here: https://www.theguardian.com/small-business-network/2017/nov/06/at-the-mercy-of-your-inbox-how-to-cope-with-email-overload
The data from the Redicati group can be seen here: http://www.radicati.com/wp/wp-content/uploads/2017/01/Email-Statistics-Report-2017-2021-Executive-Summary.pdf