Sources
Pet Statistics
http://www.aspca.org/about-us/faq/pet-statistics.aspx
Pet Euthanasia
http://www.americanhumane.org/animals/stop-animal-abuse/fact-sheets/animal-shelter-euthanasia.html
Pet Stats 2
http://www.humanesociety.org/issues/pet_overpopulation/facts/pet_ownership_statistics.html