@maxdancona,
The stats you are quoting are from 1997 -that could be the discrepancy.
"Unfortunately, the most recent statistics published by the National Council are from 1997, and only 1,000 shelters replied to the survey at that time. Using the National Council’s numbers from 1997 and estimating the number of operating shelters in the United States to be 3,500 (the exact number of animal shelters operating in the United States does not exist), these estimates were made:
Of the 1,000 shelters that replied to the National Council’s survey, 4.3 million animals were handled.
In 1997, roughly 64 percent of the total number of animals that entered shelters were euthanized — approximately 2.7 million animals in just these 1,000 shelters. These animals may have been euthanized due to overcrowding, but may also have been sick, aggressive, injured or suffering from something else.
56 percent of dogs and 71 percent of cats that enter animal shelters are euthanized. More cats are euthanized than dogs because they are more likely to enter a shelter without any owner identification."