This gradually became a wide schism as rock splintered into several formats in the early 1980s. As a result, AT40's weekly playlist could be very diverse in the styles and formats of the songs played. Historians have noted that no one station actually played all of the songs on the "Billboard" Hot 100 list, because they represented overlapping formats, such as hard rock, mainstream rock, heavy metal, dance, new wave, punk, rap, pop, easy listening/adult contemporary and country. Stations tended to specialize in only one or two of these formats and completely ignore the others.