The delivery statistics show the ratio of email addresses to which an email campaign was sent (addressees) compared to recipients who have actually received the email campaign. The addressees who have successfully received an email, are then known as recipients. The stated percentage shows the delivery rate (addressees in relation to recipients).
The difference between addressees and recipients can be different sources of error: syntax error, text in email field, no @ sign in the address, full mailbox, unknown email addresses, server timeouts, etc. The error messages can be listed and edited by clicking on Bounces. This allows that bounced email addresses are filtered and can be simply revised.
The Bounces are shown in relation to the top 10 domains, which emails have been sent to. This way you can see whether a domain generally produces a high error rate.