From 1952 to 1985, the IMS Radio Network was the only outlet for live coverage of the Indianapolis 500. Television coverage on ABC at the time was a tape-delayed format, and for only a very brief time (1965–70) MCA aired a closed-circuit live telecast of the race. The radio broadcast was the primary coverage of the race for most fans in the U.S. and around the world, including many thousands at the track itself. The network experienced its heyday of popularity from the 1960s to the early 1980s. During the late seventies and early eighties, its affiliate count swelled to over 1,200 stations. Along with shortwave transmissions, and various foreign language translations, the network boasted at one time over 100 million listeners worldwide.