IPv6 Traffic Statistics
This page shows the traffic generated by the PoPs of SixXS. Note that it indeed is only a mere fraction compared to IPv4 traffic. Also note that the values are 5 minute averages, as such short but big spikes will not be visible. Comparing it to AMS-IX though shows that we are at 25% of that traffic amount.
As can be seen from these graphs, there is a lot of capacity left on the PoPs, as such, when you have a good use for doing a lot of IPv6 traffic, do so. (Of course simply sending/receiving junk traffic is not what we mean here).