Sponsorship insights tab under Events provides you a complete insights on sponsorship events.
The following list provides you the complete details that can extracted from the Sponsorship Insights:
Name of the event sponsored
Year in which the even was organized
Name of the employee who has submitted the even sponsorship
Closed date when the event got closed
Tier provides type of sponsorship provided to the event
You can check the sponsorship details for last four years or all time details.