About 90% of American homes can receive sound in stereo from at least one local TV channel, a newsletter survey has found.
Television Digest reported that just over 25%--or 337--of all TV stations in the United States transmit some programs in stereo.
The figure stood at about 250 when the year began.
A special receiver is required to be able to hear the shows in stereo.
NBC broadcasts about 70% of its prime-time schedule in stereo, and used stereo for the first time for the World Series coverage this year. The other networks transmit far less.
NBC began accepting and broadcasting advertisements in stereo on a full-time basis on Sept. 22. That network also broadcast the first show in Dolby surround-sound, the Oct. 27 broadcast of "Amazing Stories."
The Electronics Industries Assn., a trade group, predicts that about 20% of the 17.3 million color TV sets sold this year will be equipped it receive stereo.