I track and graph the changes in the number of devices that are in Compliance using a graph function in NCM's Config Summary page. Maybe this might be what you're looking for?
First Customize the page and add a new feature to one of its columns. If Overall Policy Violations is there in that page already you could simply edit it using the info below. If it's not in any of your columns, add in Overall Policy Violations to the column and Click Done and view the page.
In the newly-added feature, (or if you're editing the pre-existing Overall Policy Violations window) click Edit in its upper right area.
Go to the drop-down for Select Policy Report. Choose the specific report you want to display and graph.
Then change the Page's Title to give it an appropriate name.
Select the Granularity and Time Frame.
Then click Submit.
If you don't see a Policy Report that fits your compliance needs, I can send you instructions with screen shots.
Hoping this is what you need, and wishing you and your clients Swift Packets!
Rick S.