Active vs Inactive Proxies

I am building a report that shows our Auditors Proxy Assignments in our application (who can Proxy for someone else) and understand that most data can come from sys_user_info. However, I am looking to see where I can pull dates from for the Proxy Assignment. We have several users that show as Proxy for someone else but they are not technically active as the end date for their proxy assignment has passed. So, even though they show as a proxy for someone, they cannot Proxy for them.

Where can I grab those dates from that are tied to the Proxy assignment?