"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 singles 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.