You can view the reports by following these steps:

1. Login to Plesk Control Panel
2. Click on the Report icon
3. Click on the Web Stats icon
4. Find the 'Select Period' drop down and select the month you want to view

Note: Make sure that the pop-up blocker is turned OFF in your browser, as the reports will show up in a popup window.  If you don't see anything happen after clicking the Web Stats icon, your pop-up blocker is likely on.