Overseer has long supported reporting on the availability of resources. This is often used by ISPs to determine their uptime for service level agreement reasons. This used to be only available on screen, but with Overseer 4.x, we added the availability report.
Overseer 5.0 enhances the availability report further, by allowing you to pick an interval– hourly, daily, etc. This lets you see your availability in % based on each segment of time in your date period, at the intervals specified.