Since the late 1890s, popular songs, initially published as sheet music for the piano, have sold millions of copies and have become a part of American popular culture. A piano was an important part of many middle class homes, as well as in schools and entertainment venues for both children and adults. During the 1920s, commercial radio broadcasting quickened the pace of public awareness, as more and more people heard and then sought the latest tunes. The first half of the 20th century saw the peak of popular sheet music production, reflecting the latest fashions in music, from ragtime to rock and roll, and often paired songs with dramatic cover artwork. This sheet music reflects the style, sentiment, and currents in the culture of its time.