How to restrict Manager evaluation to a specific number of Excellent, very good etc..

Summary:

Business want to restrict Manager to not exceed 10% of Excellent performance document within their departments, any ideas?

Content (required):

So system has to check when Manager is evaluating employee how many Excellent performance document Manager has evaluated and in case he number exceeded the allowed percentage system should not allow Manager to submit evaluation.

Version (include the version you are using, if applicable):

23B

Code Snippet (add any code snippets that support your topic, if applicable):