The data was compiled on Monday and given to the BBC on Tuesday to be announced on Johnnie Walker's afternoon show and later published in Record Retailer (rebranded Music Week in 1972).
The longest duration of a single at number-one was nine weeks and this was achieved on three occasions: "Bohemian Rhapsody" by Queen in 1975; "Mull of Kintyre" / "Girls' School" by Wings in 1977 and "You're the One That I Want" by John Travolta and Olivia Newton-John in 1978.
[3] "Mull of Kintyre" was also the biggest selling song of the decade and was not surpassed in physical sales until 1984 when Band Aid released "Do They Know It's Christmas?".
[5][nb 1] In 1977, the BPI held an awards ceremony at Wembley Conference Centre to mark the Silver Jubilee of Elizabeth II.
Five number-ones – ABBA's "Dancing Queen", Ian Dury and The Blockheads' "Hit Me with Your Rhythm Stick", The New Seekers' "I'd Like to Teach the World to Sing (In Perfect Harmony)", Julie Covington's "Don't Cry for Me Argentina" and Pink Floyd's "Another Brick in the Wall (Part II)" – passed the million-sales mark following the introduction of music downloads in 2004.