The chart only uses sales of permanent digital downloads, that is single-download tracks on non-subscription online music stores.
[3] One year later, a limited edition re-release of "One Night" / "I Got Stung" by Elvis Presley topped the chart with 22,000 copies, making it the lowest selling number-one single at that time.
[7] As a result of this growth, the OCC were commissioned in 2004 to compile a new music chart based solely on the UK's download sales, which was initially sponsored by Coca-Cola.
[8] A "sample" download chart was trialled for 10 weeks, with the first number one being "Bam Thwok" by American rock band Pixies.
[14] By 2007, the UK had become Europe's largest consumer of online music, with almost 78 million tracks being downloaded that year; by 2012, this figure had more than doubled.