I report my kills as well, and make sure everyone that hunts with me does the same. These stats are not based on tangible numbers, they are estimates because people fail to report either by forgetting or breaking the law. Maybe we should call these estimatistics or something, but its better then nothing.
As a side note, I went to the butcher near my property 3 times, the majority of the bucks he saw come into the shop were larger then the previous years both in antler size and body size. He also said the DEC was there quite often, and asked him to keep some stats for them as well. The DEC is undermanned for any type of mass enforcement, it is what it is, and its never going to change.