This will need to be created in a list, to create a list navigate to:
  1. Navigate to Lists > Manage Lists
  2. Click the Manage basic and advanced lists block under List Actions
  3. Click the List Templates tab
  4. Category: Constituent Information titled :Registered Students (Current Year and/or Next Year).
  5. Click View/Copy.
  6. In Select Objects expand the Platform Object, select Grade Level.User-added image
  7. Click Display Fields 
  8. Click Select Fields
  9. Expand User Register, Grade Level
  10. Select Grade Level or Grad Level Description depending on if you want the long or short Grade Item
  11. Click Select
  12. Click Filters and remove the Global Filter that exists
This will show one row for each grade for each user, from here you can see the Enroll and Depart Dates which shows which grade they were in at that time.

You can filter more specifically if you only want users in the Student Role, as this list will pull Students who have a school registration record for the current school year and Incoming Students who have a school registration record for the next school year and Past Students who were registered for the current school year and have subsequently been withdrawn.