The music of Hawaii includes an array of traditional and popular styles, ranging from native Hawaiian folk music to modern rock and hip hop. Hawaii's musical contributions to the music of the United States are out of proportion to the state's small size. Styles like slack-key guitar are well known worldwide, while Hawaiian-tinged music is a frequent part of Hollywood soundtracks. Hawaii also made a contribution to country music with the introduction of the steel guitar. In addition, the music which began to be played by Puerto Ricans in Hawaii in the early 1900s is called cachi cachi music, on the islands of Hawaii.