edit- I see now that I completely misread dollars as bitcoins. My response actually makes sense in that context, and not so much to the question you actually asked.
My understanding is that it would be impossible to know. How could you tell the difference between a dollar that was being hoarded, a dollar that had simply not been spend yet, or a dollar that it's owner had lost access to? The way the system is set up, it is supposed to be impossible to tell even how much money a single individual possesses. One person could own half of all the bit coins in a massive market manipulation attempt right now, and I don't know how anyone could figure it out.
My understanding is that it would be impossible to know. How could you tell the difference between a dollar that was being hoarded, a dollar that had simply not been spend yet, or a dollar that it's owner had lost access to? The way the system is set up, it is supposed to be impossible to tell even how much money a single individual possesses. One person could own half of all the bit coins in a massive market manipulation attempt right now, and I don't know how anyone could figure it out.