1) How does one determine if a flight is overbooked? This is not easily available to the public.
2) How do you know the circumstances of an overbooking? Previous cancellations, other airline cancels, downgrade of aircraft, day of week changes, weather etc.
3) Why do we care if a flight is overbooked and everyone is accommodate or took the compensation?
4) Isn't this what Revenue Management is for?

Basically this kind of tally will be meaningless to determine anything other than specific anecdotes of one flight on one particular day. I'm not sure it provides any other value.