The Arbor Networks Security team has posted some analysis and graphs of the recent DNS flaw:

Given that this vulnerability was partially disclosed on July 8, I suspect a great deal of this traffic is name server vulnerability scanning, as opposed to malicious cache poisoning attempts, although there may well be a mix of the latter.

Nice visualization. The flaw was more officially known or “in the wild” on the 24th, and certainly known by the 27th, so a critical week is missing here.