Since the middle of the 19th century, Americans purchased pianos in increasing numbers. Families and friends gathered around the piano for evenings of musical fun. Piano players needed sheet music to learn the latest songs and publishers quickly printed everyone's favorite pieces, first in black and white and later with detailed chromolithographed color covers. The advent of radio and even television simply increased public awareness of hit songs, and the production of sheet music still grew. Eventually, use of sheet music lessened along with the popularity of home pianos in the middle and later 20th century. Radio, phonographs, and personal listening devices began to replace the piano in the parlor. The music of "Mockin' Bird Hill" is based on the Swedish waltz "Livet i Finnskogarna" or "Life in the Finnish Woods," published in 1915. This version, sung by Patti Page, lasted 22 weeks on the Billboard pop music chart, beginning in 1951. It is mentioned in the song "Spanish Bombs" by The Clash.