I can start us off, if you like.
First of all, a DG leaker is also referred to as a non-accidental release. That really means it's a shipper-caused issue, like a faulty O-ring or a valve that's not fully closed, and there's a venting from the car. It could be an overload, and it's a pressure release. Those are the kind of circumstances that lead to DG leakers.
The other statistic you referred to is really just about involvement of dangerous goods within a train, but not necessarily that they were involved in a derailment, that there was any release.
One of the key stats in the TSB's website is accidents involving a release, and the annual average is usually in the area of two to three per year. It's actually very simple to come up with the 99.997% that was discussed earlier by simply taking the number of shipments. Combined dangerous goods shipments on CN and CP are approaching about a million a year, and yet you can see from the TSB's own statistics that there are in the area of two to three accidents involving a release. As we talked about earlier, that can be any release, literally picking up a shovelful of pellets.