Remaining Enrollment Seat Count sample (OHUG 2016)
SummaryOLBR from OHUG 2016 sample
I showed this report as an example in my OHUG 2016 session (original thread here).
This report leverages a custom RTF layout that summarizes the number of users in an "Approved" pre-status in the selected Enrollments. It also displays the remaining available seat count for each Enrollment.
The RTF also displays a bar graph for the number of users in each pre-status, not just "Approved".
After you have imported the OLBR, you will need to run the report once so you can enable the Modify Layout action. After you run the report, upload the associated RTF using the Modify Layout action.