To find out the number of notifications you’ve sent you will be directed to dashboard after logging in with your registered account.

On the left side(vertical navbar) click on Notification > Sent Notification.

You will then find the number of notifications you’ve sent to users.

Click on Export Data. 

You will then get a file which has a record of a number of notifications you’ve sent, view count, date time etc. Delivery count and sent counts means the same.