Such nuisance calls were sharply reduced after the 2003 creation of the federal do-not-call list, which prohibits telemarketers from phoning people who have registered.
Despite the popularity of the registry, which has grown to more than 150 million numbers, there had been worries that some home phones could begin ringing again with sales calls this year because of a rule requiring consumers to re-register after five years.
Congress is working to fix that: Legislation passed by the House and Senate aims to make permanent the registrations on the do-not-call list maintained by the Federal Trade Commission.
Sen. Byron Dorgan, a Democrat from North Dakota who sponsored the legislation, said he expects the nearly identical bills to be reconciled and sent to President Bush for signature by the end of this month.
Mr. Dorgan pointed out that the do-not-call list "has to rank among the most popular programs in history."
As he put it, "Not only did the American people respond to the original legislation -- they responded immediately, and en masse."
The new bill, he said, fixes a glitch in FTC rules.
"Certainly, people didn't want to have their names removed from the list and have to come back to the government to create a new list," he said. "That makes no sense."
The FTC has acknowledged the problem and pledged not to drop any telephone numbers based on a five-year limit "pending final congressional or agency action on whether to make registration permanent," according to testimony before Congress last fall by the FTC's director of consumer protection, Lydia Parnes.
The agency said the rule requiring re-registration every five years originally was adopted to try to keep the list as fresh as possible.
Since 16 percent of phone numbers change every year and 20 percent of Americans move each year, the thinking was that a re-registration requirement would help eliminate numbers no longer in use or that had been assigned to others.
But the FTC found that changes including "increased usage of cell phones and increased popularity of telephone number portability" had made that unnecessary. Also, a "scrubbing program" developed in cooperation with local phone exchanges automatically eliminates disconnected or reassigned numbers, it said.
Most importantly, it concluded: "The registry has enjoyed unprecedented popularity and helped enhance the privacy of the American people in a tangible way."
One reason for the heavy participation is that the government has made it easy for people to register.
Families can register their home phones or cell phones on the Internet at www.donotcall.gov or by calling the toll free number (888) 382-1222. Telemarketers must stop calling no later than 31 days after the registration takes place.
The Web site and phone number also can be used by consumers to delete a registration. And consumers can use them to file a complaint against a telemarketing company that doesn't honor the listing. The FTC has gone after violators and so far has collected more than $17 million in fines.
There are groups that are exempt from the do not call regime -- political organizations, charities and telephone surveyors. Other exceptions are for companies that consumers have an existing business relationship with or that consumers have given permission in writing to call.
ON THE NET
Do-not-call registry: www.donotcall.gov