Country music is a blend of popular musical forms originally found in the Southern United States and the Appalachian Mountains. It has roots in traditional folk music, Celtic music, blues, gospel music, hokum, and old-time music and evolved rapidly in the 1920s. The term country music began to be used in the 1940s when the earlier term hillbilly music was deemed to be degrading, and the term was widely embraced in the 1970s, while country and western has declined in use since that time, except in the United Kingdom, where it is still commonly used.
Country music has produced two of the top selling solo artists of all time. Elvis Presley, who was known early on as “The Hillbilly Cat” and was a regular on the radio program Louisiana Hayride, went on to become a defining figure in the emerging genre of rock 'n roll. Garth Brooks is one of the top-selling country artists of all time, and except for a short foray into non-country in the late 1990s, has remained in that genre. While album sales of most musical genres have declined, country music experienced one of its best years in 2006, when, during the first six months of the year, U.S. sales of country albums increased by 17.7 percent to 36 million. Moreover, country music listening nationwide has remained steady for almost a decade, reaching 77.3 million adults every week according to the radio-ratings agency Arbitron Inc. The term country music is used to describe many styles, genres, or subgenres.