During the 20th century there was a large increase in the variety of music that people had access to. Prior to the invention of mass market gramophone records (developed in 1892) and radio broadcasting (first commercially done ca. 1919–20), people mainly listened to music at live Classical music concerts or musical theatre shows, which were too expensive for many working class people; on early phonograph players (a technology invented in 1877 which was not mass-marketed until the mid-1890s); or by individuals performing music or singing songs on an amateur basis at home, using sheet music, which required the ability to sing, play, and read music. These were skills that tended to be limited to middle-class and upper-class individuals. With the mass-market availability of gramophone records and radio broadcasts, listeners could purchase recordings of, or listen on radio to recordings or live broadcasts of a huge variety of songs and musical pieces from around the globe. This enabled a much wider range of the population to listen to performances of Classical music symphonies and operas that they would not be able to hear live, either due to not being able to afford live-concert tickets or because such music was not performed in their region.