Accurate data is hard to come by as there is no single, national system for recording it, and the various surveys calculate different results, but...
6.3 million animals enter shelters nationwide each year.
The Best Friends Animal Society suggest 8% of animals entering shelters, or 378,000 animals, are killed each year.
Though the Humane Society of the United States says number is more like 750,000 healthy and safe animals are killed (not counting those who are euthanized for medical or safety reasons) and Spots.com says that 9 out of 10 animals that are killed are actually adoptable with no medical issues.
According to the American Society for the Prevention of Cruelty to Animals (ASPCA), that number jumps to 15% of animals entering shelters, or 920,000 animals, are killed each year.
And, according to American Humane, up to 56% of dogs and 71% of cats that enter shelters are killed.
Spots.com suggests that between 4,000 and 10,000 animals are killed in shelters every day (equalling 1.5 to 3.5 million animals per year) and that up to 57% of those killed are unweaned kittens.
Most of these killings, about 52%, happen in one of five states: Texas, California, North Carolina, Florida, and Louisiana.
As a whole, the nation pays $1.5 billion - that's $1,500,000,000 - each year for animal control, euthanasias included.
90% of homeless dogs are pit-bulls and, when in shelters, 93% of pit-bulls are killed.
Racing greyhounds are often homeless and killed after their "retirement" from a racing career that often lasts only 2-3 years, less if the animal is injured. Over 1.35 million - that's 1,350,000 - greyhounds have been killed since the sport began.
Black cats the least adopted and the most euthanized of cats.