Show summary of run time

It would be extremely useful if we could see a simple view that shows the run time for each unit over a given time period. Both in time and percentage. Bonus would be to include something that indicates a change month over month or week over week.

I recently found that one of my units is performing poorly. Initially it was just me looking at the temp and thinking “Hmmm, it should be lower”, then I used beestat to look at the run time in the Thermostat Detail graph. But a simple chart of run time would be very useful for me to be able to see if a unit is running more than usual.