Well I think a more accurate projection would be tallying up all the units dlink has sold. of all the reivisions.
subtract the h/w a1 units
of the remaining unites, take seventy percent or so away due to the fact that its likely that number doesn't bother upgrading their routers firmware because they have no knowledge and are too timid to do so because they dont' want something to go wrong. The remaining 30 percent, than is a more accurate plausability than your less than one percent.
This is why playing percentages is always shady.
Out of that 30 percent, then have upgraded their routers to 1.2+ ? Now you can summerize that it is indeed firmware related.
I can atess to that since I never encountered this problem before upgrading the f/w. As well never reported it until when I did because I didn't catch on to the trend and thought it was just someone torrenting.
However, i'm still tryign to find something in common with this 4/5 day router freeze