There are two options to see how many photos you've printed. First go to your GoPhoto - CMS and login with your credentials.
At the top of the dashboard you can find how many photos you've printed this month. This bar resets at the beginning of every month.
When you scroll down a bit you find 'Upload & Sales statistics'. Here you can see how many photos you've printed that day.
Statistics - System
When you want to see an overview of how many photos you've printed over a different period of time go to 'Statistics' - 'System' in the sidebar.
Here you can change the date and get an overview over a different period of time. You can see how many small, large or other photos you've printed. You can view these statistics daily, weekly, monthly or yearly.