You can view how many emails have been sent through your account by viewing the Email Usage report.
Click Settings or the Gear icon on the left menu.
Click on the Communication tab.
Click the Email Usage link in the Email Reports section.
The Email Usage report displays. By default, it displays the last month worth of emails. You will see the following details on the page:
Email Volume Limit - Displays the organization’s annual and monthly average email limits
Usage To Date - The total number of emails that have been sent throughout the year to date.
Date fields and the Generate Report button - If you want to see different dates in the report, you could enter a new date range in the date fields and click the Generate Report button. This will reload the page to display the emails sent from the new date range.
Chart Columns
Account - The account name that sent the emails.
Batches Sent - The total times an email batch was sent.
Emails Sent - The total number of individual emails sent.
Total Size - The size of the email in KB (kilobytes).
To view the email’s individual statistics, click the Details link in the Actions column. This will take you to the Email Traffic report page.