Nowadays, almost all dog owners make sure to spay or neuter their dogs, which is good. Due to education and development in spaying and neutering surgeries. Besides the assessment from the No Kill Movement, the number of dogs euthanized in shelters from overpopulation decreased by 90% in the last 50 years though.
That means shelters euthanize a big number of dogs every year in the US because of overpopulation. All dog lovers have to be careworn about that sad info. Therefore, the ultimate way to help those poor dogs is to spay or neuter your own dog. No puppies mean no overpopulation, not so crowded shelters, and lower euthanasia rates.