DIAGRAME

A  record chart , also called a  music chart , is a ranking of  recorded music  according to certain criteria during a given period of time. Many different criteria are used in different charts, including  record sales , the amount of radio  airplay , and since the popularity of the Internet for music, the number of  downloads  and the amount of  streaming  activity. Some charts are specific to a particular  musical genre  and most to a particular geographical location (although download charts are not easily pinned down in this way). The most common period of time covered by a chart is one week with the chart being printed or broadcast at the end of this time. Summary charts for years and decades are then calculated from their component weekly charts. Component charts have become an increasingly important way to measure the commercial success of individual songs.