like iHeartMedia. There are also many small independent local stations. National Public Radio (NPR) is the public radio network. Radios: 575 million (1997) Television In 1948, 1 percent of U.S. households owned at least one television while 75 percent did by 1955, and by 1992, 60 percent of all U.S. households received cable television subscriptions. In 1980, 1 percent of U.S. households owned at least one videocassette recorder while 75 percent did by 1992. Television broadcast stations: 7,533 (of which 1,778 are full-power TV stations; 417 are class-A TV stations; 3,789 are TV translators; and 1,966 are other low-power TV stations) (as of December 31, 2016, according to the Federal Communications Commission); in addition, there are about 12,000 cable TV systems. Most local commercial television stations are owned-and-operated by or affiliated with the large national broadcast networks such as the American Broadcasting Company (ABC), CBS, the Fox Broadcasting Company (Fox), the National Broadcasting Company (NBC), and The CW Television Network. Some television networks are aimed at ethnic minorities, including Spanish-language networks Univisión and Telemundo. The Public Broadcasting Service (PBS) is the country's main public broadcasting network, with over 300 non-profit affiliated stations across the United States. Besides the large broadcast networks (which are free for anyone with a TV and an antenna), there are also many networks available only with a subscription to cable or satellite television, like CNN. Televisions: 219 million (1997) Internet Internet Service Providers (ISPs): 7,600 (1999 est.) Because of aggressive lobbying and the United States' strong libertarian traditions, the Internet service provider industry remains relatively unregulated in comparison to other communications industries. Country code (Top level domain): US For various historical reasons, the .us domain was never widely used outside of a small number of government agencies and school districts. Most companies signed up for top level domains like .com instead. NeuStar Inc. now has control over the .us registry and is trying to promote the domain as an option for American-oriented Web sites. See also Big Three television networks Cable television in the United States Communications in the United States Fourth television network High-definition television in the United States List of television stations in the United States List of United States cable and satellite television networks List of United States over-the-air television networks List of United States television markets Satellite television in the United States Television in the United States Television news in the United