Irish traditional music has remained vibrant, despite globalising cultural forces, and retains many traditional aspects. It has influenced various music genres, such as American country and roots music, and to some extent modern rock. It has occasionally been blended with styles such as rock and roll and punk rock. Ireland has also produced many internationally known artists in other genres, such as rock, pop, jazz, and blues. Ireland's best selling musical act is the rock band U2, who have sold 170 million copies of their albums worldwide since their formation in 1976.