Your record is based on the number of consecutive days your inbox has remained at zero emails. That is, the number of successive days with at least once a day an empty Inbox. It will appear on the main screen of your Inbox. To check it:
Writing a new email is only a few clicks away.
You might have had emails in your Inbox, but they might have disappeared from your inbox after being read and sorted in conversations with contacts. Moreover, with the Serenity Mode activated, only some of your emails will appear in your inbox. To see the options go to: