Progress reporting over time is only available for Imported Lists. On the back of a Imported List Report Card, you can click on Progress Report to see the List Quality Score over time.
The Progress Report view shows:
Current List Quality Score
Current number of subscribers
Date the list was imported to DataValidation
ESP account details
Date grades were last synced to ESP list (occurs at purchase, daily during Assurance)
Data points with Email Assurance Grades
Calendar view to see progress over time
By clicking on the first data point you can see what your list looked like at the time of import, with details on the percentage of emails that have each Email Assurance grade. You may need to adjust to calendar view as the default view only shows the past 2 weeks.
Your imported lists are scanned once a day to check for newly added subscribers. Any new lists in your ESP are also imported at this time. As individual list data changes, the List Quality Score will trend in the corresponding direction. It's free to monitor your lists for as long as you like.