Benefit Eligibility versus Election Report?

Summary

Trying to determine who was elegible, and of those, who elected

Content

I'm trying to find or build a report that prompts for a date, plan, and will then show all the employees who were eligible to elect the plan, and whether they did.  That is, not just enrollments but anyone who was even eligible to enroll.  Does anyone have something like this or similar?  Or, some helpful hints?  

Many thanks in advance!