I'm still curious to know what your guess would be Snoopy? I take it you feel most of the value is reported then?
Would guess maybe 20% gets reported. Would say the same thing about any extension.
The key thing is though that the known quantity is what is reported & that is the clearest indication of what is happening.
The NDA/unreported sales argument is brought out when the sales are bad, it is used as an an excuse, usually in regards to alt TLD's, but also mainstream extensions where the figures point to a decline in prices.