(CNN) -- Larry William Swilling walks the streets of Anderson, South Carolina, with a sandwich board over his stocky shoulders.
"NEED KIDNEY 4 WIFE," the sign reads.
He and Jimmy Sue Swilling have been married for 55 years. She was born with only one kidney and after years of kidney disease, that organ has started to fail. No one in the family is a match for a transplant.
Swilling, 77, has collected six pages of names of strangers who offered to be tested as potential kidney donors for his wife.
"I never would have thought that I'd have got this much response to it," Swilling told CNN affiliate WYFF with tears in his eyes. "I'm amazed by it and I'm so thankful."
Approximately 92,000 people are on the waiting list for kidney transplants in the United States, according to the National Kidney Foundation. Last year, 4,903 of them died waiting.
The United Network for Organ Sharing manages the U.S. transplant system under a contract with the federal government. The kidney is one of the most needed and most transplanted organs, said UNOS spokesman Joel Newman; it's not uncommon for patients to wait three to five years for a deceased donor's organ.
That's why many patients reach out to family or friends for help in finding a living match.
Swilling is not the first person to go public to find an organ donor. In 2004, cancer patient Todd Krampitz advertised on highway billboards for a new liver and was successfully matched. Earlier this year, 21-year-old Hannah Craig found a kidney donor on Facebook. Even a member of Anderson Cooper's team has asked the show's audience for help.
There's been an uptick in recent years of altruistic donors, says Dr. Brian Becker, a transplant physician and former president of the National Kidney Foundation.
"It is far more common than it was even two years ago for people to step forward."
Becker said there are a growing number of donor chains in the United States where people who aren't a match for a family member or friend can sign up to donate to a stranger, in hopes that someone else in the chain will be a match for their loved one.
"These are novel ways that people are trying to identify how to best get kidney donations to the people that need them," Becker said.
OrganDonor.gov says more than 100 million Americans are registered organ donors, but it's not enough to keep up with the demand.
"We could save thousands more lives a year if we had another 20, 30, 40 million more people registered," David Fleming, president and CEO of Donate Life America, told CNN in May. DonateLife.net is partnering with Facebook to increase the number of registered donors through social media.
Part of the reason kidneys are in such high demand is the transplant operation's success rate, Newman said.
With transplants from deceased donors, patient survival rate at three years is 90%, according to UNOS data. At 10 years, it's 62%. The rate is slightly higher for living donor organs.
As with any surgery, living organ donors are also at risk. But Becker says kidney transplants are some of the safest; a donor can live with one kidney for the rest of his or her life.
"I think people see the fact that they can donate a kidney to help somebody out," he said, "and recognize that they themselves can still live a long and healthy life."
Swilling's volunteers will be tested this week for free at a local clinic, according to WYFF. If anyone is a match for Jimmy Sue, that person will be put through several physical and psychological tests to ensure he or she is able and willing to go through with the transplant surgery.
In the meantime, Swilling says he will continue to walk the streets in hopes of saving his wife's life.