Also: Animal euthanasia rates have plummeted since the 1970s — find out why more dogs and cats are making it out of shelters alive. Plus, learn why optimists live longer,

When a lost, stray or abandoned pet entered a U.S. city’s animal shelter 10 years ago, there was a good chance it would not leave.

But in a quiet transformation, pet euthanasia rates have plummeted in big cities in recent years, falling more than 75% since 2009. A rescue, an adoption or a return to an owner or community is now a far likelier outcome, a shift that experts say has happened nationwide.

The New York Times collected data from municipal shelters in the country’s largest 20 cities. Many of the shelters do not track outcomes uniformly or make historical data readily available online. Until recently, there has not been a concerted national effort to standardize and compile shelter records.

One reason the data is scarce: What it represents is sensitive. Even in the best-run shelters, workers face criticism, even death threats, for euthanizing animals.

For much of their history, cities’ animal services swept stray dogs off the streets, brought them to the pound and put them to death. (It wasn’t necessarily heartlessness; there was a well-founded fear of rabies).

Since the 1970s, large-scale activism, industry professionalization and shifting cultural attitudes have helped limit euthanasia to fewer than 2 million shelter animals per year.

“They’re family members on four legs,” said Richard Avanzino, a longtime activist known as the father of the “no-kill” movement. “Society is no longer willing to say, ‘Well, there’s just too many animals and not enough homes.’”

Animal welfare experts tend to agree that since the 1970s, the number of stray animals entering U.S. shelters has decreased sharply — the result of a successful push to promote spaying and neutering of pets (remember Bob Barker’s signoff on “The Price Is Right”?).

A recent paper in the journal Animals found that up until about 2010, the drop in shelter euthanasia tracked very closely with the drop in intake. After that, the authors wrote, it appeared that adoptions helped to further drive down euthanasia rates.

Nearly all of the shelters in the Times analysis increased adoptions over the 10-year period surveyed.

“Rescuing an animal has become a badge of honor,” said Matt Bershadker, president and chief executive of the American Society for the Prevention of Cruelty to Animals. “People proudly go to dog parks and walk around their neighborhoods talking about the animal that they rescued from a shelter.”

Many of the animals rescued are transported north from Southern states with higher rates of euthanasia. The ASPCA alone relocated 40,000 animals in 2018.

Most of the shelters in this analysis also continue to reduce the number of animals they take in. Programs to spay/neuter and release community cats are one factor. There has also been a rise in programs helping people resolve problems — like landlord disputes and unaffordable vet care — that might otherwise compel them to give up their pets.

ILANA PANICH-LINSMAN / NEW YORK TIMES Hailey Juarez, 6; Emmanuel Guerrero, 7; and Zitlaly Guerrero, 5, visit Nixon, a dog at Dallas Animal Services, in August. In a cultural shift, rescue adoption’s popularity has soared.