Billboard Hot 100 (1970-79)
The Billboard Hot 100 is the United States music industry standard singles popularity chart issued weekly by Billboard magazine. Chart rankings are based on airplay and sales; the tracking-week for sales begins on Monday and ends on Sunday; while the airplay tracking-week runs from Wednesday to Tuesday. A new chart is compiled and officially released to the public by Billboard on Thursday. Each chart is dated with the “week-ending” date of the following Saturday.
Billboard’s “chart year” runs from the first week of December to the final week in November. This altered calendar allows for Billboard to calculate year-end charts and release them in time for its final print issue on the last week of December. Prior to Nielsen SoundScan, year-end charts were calculated by an inverse-point system based solely on a song’s performance on the Hot 100 (for example, a song would be given one point for a week spent at position 100, two points for a week spent at position ninety-nine and so forth, up to 100 points for each week spent at number one). Other factors including the total weeks a song spent on the chart and at its peak position were calculated into its year-end total.
After Billboard began obtaining sales and airplay information from Nielsen SoundScan, the year-end charts are now calculated by a very straightforward cumulative total of yearlong sales and airplay points. This gives a more accurate picture of any given year’s most popular tracks, as a song that hypothetically spent nine weeks at number one in March could possibly have earned fewer cumulative points than a song that spent six weeks at number three in January. Interestingly, songs at the peak of their popularity at the time of the November/December chart-year cutoff many times end up ranked lower than one would expect on a year-end tally, yet are ranked on the following year’s chart as well, as their cumulative points are split between the two chart-years.
Click on the year to view the Hot 100 chart for that year:
To view a summary of all the Billboard Hot 100 lists of from the 70’s click the Billboard Tag or click here.
For more information please visit the Billboard Hot 100 Wiki.