Most likely, they are counting instances where folks innocently try to do something that is against a ridiculously complicated law. For example, at the Exchange, all the time, we get customers who have Exchange privileges trying to help a buddy get the kind of good deal that is available at the Exchange. They aren't trying to break the law. However, when we discover that a purchase is really for someone without the privilege, we stop the transaction as a potential straw purchase. No one was trying to obtain a firearm that he cannot legally possess, yet the transaction would technically be a straw purchase. Such an attempt would probably be counted.
They probably also count when someone says, "Here, use my credit card," also a technical straw purchase. Or, how about when a customer comes in from Indiana. We spend twenty minutes with him selecting a handgun. Then when we ask for an Ohio DL, he tells us he lives in Indiana. We can't sell him a handgun (stupid law), but the lefties would probably count that attempt too.
It ain't always someone trying to break the law. In my experience, the only sales I have had to stop were sales where the buyer simply did not know the intricacies of the law. But that is what these laws do. They trap the well-meaning, but ignorant, law-abiding citizen. The crooks will just do what they will, the law be damned.