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 99 and so forth , up to 100 points for each week spent at number one ) .
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 ) .