That's a very interesting point. Did you try to figure out which could be the percentage of the Bitcoins which get traded versus the total supply?
To do it one would have to compare statistics from all exchanges around the world, or at least all of the biggest ones in every country.
If we take a single exchange like bitfinex and compare some of the recent pump and dump schemes we'll at least have a confirmation of what's going on.
January 22 (dump) 6200 btc in 2 h
January 23 (pump) 5900 btc in 2 h
January 26 (dump) 7200 btc in 2.5 h And on the same day there was a quick rebound during which almost 6000 coins were bought back in a little over an hour.
I believe the ones buying back are the same people that were selling during the dump, there's no significant price movement because there's no fresh coins or money coming to the exchanges. It's always the same people playing around with newcomers bringing less than 10% of the capital to the table.
Well, this is the volume of these pump and dumps in Bitfinex, but I've seen massive pump and dumps also on Bittrex, Poloniex etc. And these are the core of the speculators. Then there are also normal traders. So the figures would be higher than the one you mention. But I agree that it's only a little share of the total Bitcoins which is moving.