How much do Americans love their dogs?

Enough to spend an annual average of $1,955 per pet to feed them, tend to their medical needs, clothe them, groom them, amuse them, and have them professionally walked, among modern canines' many needs.

But the national passion for pooches seems to wane when it comes time to license them. The large majority of owners do not make the potentially lifesaving purchase of a tag.

There are an estimated 3.2 million pet dogs in Pennsylvania, yet only about 20 percent have the required state license. The same percentage holds in New Jersey, where the canine population is about 1.3 million.

"Nationally, we know compliance is very low," said Inga Fricke, an official of the Humane Society of the United States in Washington. Though the proportion of tagged dogs varies widely from community to community, she said, those with meager means to enforce the law and scant punishment for lawbreakers can have compliance rates in the single digits.

Few places are down as dramatically, though, as Delaware County, home to an estimated 141,000 dogs.

In 2007, license sales there jumped to more than 29,000 after state wardens swept through dog parks looking for scofflaws, county treasurer John A. Dowd said. "Other than that, people don't buy licenses."

Only about 5,500 tags have been bought so far this year.

Starting July 1, having that tag around your dog's neck will become a lot more important in Delaware County.

The Delaware County SPCA, a small nonprofit that has taken in strays for a century, will no longer accept lost animals as it becomes a no-kill facility.

In recent years, the county's municipalities have dropped off about 1,400 stray dogs a year at the Media shelter. But with the deadline almost upon them, most of the 49 towns and townships still have no alternative plan for picking up and holding strays for 48 hours, as the state requires, before the animals can be put up for adoption or destroyed.

The lack of a license drastically lowers the chances of a quick reunion between a lost pup and its family.

Irresponsible owners are at the heart of the licensing problem, said Dave Schlott, animal-control officer for 13 Delaware County municipalities.

In the dozen years he has had the job, Schlott said, he has heard it all. The paperwork got lost. The dog ripped the tag off its collar. The dog hardly ever goes out anyway. And on and on.

"The people are just feeding me a line," said Schlott, who plans to retire June 30. "If they cared about their pet, they would be organized."

Karel Minor, executive director of the Humane Society of Berks County, called the lack of a tag "literally a death sentence for dogs.. . . The owner claim rate is directly related to whether or not the dog has ID."

Under Pennsylvania law, every dog older than three months must be licensed. The fees range from $6 for a pup that has been neutered or spayed to $50 for a lifetime license for a dog that has been microchipped or tattooed. If the animal is found with no license, the fine may run as high as $300.

New Jersey requires all dogs older than seven months to have licenses as well as rabies vaccinations. The cost is set by the municipalities but cannot exceed $21.

In Pennsylvania, the job of selling licenses falls to the counties, though how they go about it is varied and sometimes sporadic.

The state offers the counties a free mailing to alert residents about dog-license requirements. Last year, 30 counties did not take advantage of the service. Twenty-one sent out their own reminders.

"We actually send out a postcard," said Ava Tuturice, treasurer in Montgomery County, which sold nearly 30,000 licenses last year.

Additionally, PADogLicense.com - a private online vendor used by Montgomery, Chester, Bucks, and 22 other counties in the state - sends annual e-mail reminders to register via the Internet. Pet owners can sign up from a home computer with a credit card.

Delaware County does not use an online service.

Even with the ease of online registrations, the state rate is extremely low, said Jason Abla, president of PADogLicense.com, which reaches about 400,000 owners. "I should have two million [customers]," he said. "A lot of people are not licensing their dogs."

Abla charges the counties $10,000 for his service, which includes linking lost dogs to owners through the tag numbers. Last year, his company was responsible for 536 reunions.

Philadelphia, with an estimated 390,000 dogs, has a licensing rate of just 5 percent - an improvement over recent years.

In the next few months, the city is to begin a campaign to improve compliance with state law. It will include TV spots and billboards, said Brian Abernathy of the Managing Director's Office.

Five percent, he said, "is not a number I am proud of."

Contact staff writer Mari A. Schaefer at 610-892-9149 or mschaefer@phillynews.com.