The FTC said 3.4 million people signed up in California, 2.2 million in Florida and 2 million in Texas. Eight of every 10 people who joined the list did so online rather than by telephone.
"Millions of consumers registered their telephone numbers successfully within the first few days of the opening of the registry, and hundreds of thousands of numbers still are being entered every day," FTC chairman Timothy J. Muris said. "We want to do everything we can to make certain that consumer expectations about the Registry are met."
Telemarketers have challenged the list in court, saying the registry will cost them $50 billion in business and cause the loss of 2 million jobs.
Beginning in September, telemarketers will have to check the list every three months to see who doesn't want to be called. Those who call listed people could be fined up to $11,000 for each violation. Consumers would file complaints to an automated phone or online system.
Exemptions from the list include calls from charities and pollsters and calls on behalf of politicians. A company also may call a person on the no-call list if that person has bought, leased or rented from the firm within the past 18 months or has asked about or applied for something during the past three months.
People can register for the service by calling toll-free at 1-888-382-1222 or visiting the Web site http://www.donotcall.gov.