Its data, published by Billboard magazine and compiled by Nielsen SoundScan, is based collectively on each single's weekly physical and digital sales, as well as airplay.
In 2011, 14 singles claimed the top spot in 53 issues of the magazine, one of which, singer Katy Perry's "Firework" started its peak position in late 2010.
[3] In 2011, nine acts achieved their first US number-one single, either as a lead artist or a featured guest: Wiz Khalifa, Adele, Pitbull, Afrojack, Nayer, LMFAO, Lauren Bennett, GoonRock and Calvin Harris.
Pop singers Adele, Britney Spears, Katy Perry and Rihanna each earned two number-one songs during the year.
[2] It became only the eleventh single by a female solo artist to have spent at least ten weeks at number-one in the chart's history.