Before 78 RPM record sales began in the 1930s, one could track popular music in America by examining sheet music sales starting in the late-19th Century. The explosion in popular music created a market for music that could be brought into the home, and this meant that many minstrel performers, major and minor vaudeville, novelty, and variety artists had sheet music published with their likenesses on the cover. While rare, even sideshow performers occasionally had their own published songs printed and sold to the masses.