Top of the Pops, also known as TOTP, is a British music chart television programme, made by the BBC and originally broadcast weekly between 1 January 1964 and 30 July 2006. The world's longest running weekly music show, TOTP was shown every Thursday evening on BBC One, except for a short period on Fridays in mid-1973, and again in autumn 1974, before once again being moved to Fridays at 7:30 pm in 1996 and then to Sundays on BBC Two in 2005. Each weekly show consisted of performances from some of that week's best-selling popular music records, usually excluding any tracks moving down the chart, including a rundown of that week's singles chart. This was originally the Top 20, changing to the Top 30 during the 1970s and the Top 40 in the 80s. The distinctive TOTP theme tune – a riff of Led Zeppelin's "Whole Lotta Love" – first appeared in 1973 as the background music to the chart countdown.