and LL Cool J. The prosperous period of hip-hop was an innovation between the mid-1980s and the early 1990s (par. 4). In the 1990s, hip-hop started to intermingle with other regional styles such as Southern rap and Atlanta hip-hop. At the same time, it became more obvious that other genres of popular music had a huge influence on hip-hop. Hip-hop was gradually assimilated into other genres of popular music. Afterwards, Hip-hop became the most popular musical style in the mid-1990s and the best-selling music genre by 1999 (par. 8). Notable artists at this time include the Juice Crew, Public Enemy, Boogie Down Productions and KRS-One, EPMD, Slick Rick, Kool G Rap, Big Daddy Kane, Ultramagnetic MCs, De La Soul, and A Tribe Called Quest (par. 4). In 2004, Public Enemy ranked number forty-four among one hundred greatest artists on the list of the Immortals of Rolling Stone magazine, which was the highest ranking for a hip-hop act. Public Enemy’s famous works includes: DJ Lord, Professor Graffi, Chuck D, Flavor Flav and Khari Wynn. From 2005, sales of hip-hop music in the United States tended to seriously reduce. During the mid-2000s, the situation of decreasing sales started to take a turn for the better, partly as a result of the success of some artists such as OutKast and Kanye West (par.