Billboard Year-End charts are a cumulative measure of a single or album's performance in the United States, based upon the Billboard magazine charts during any given chart year. 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 incorporating chart data from Nielsen SoundScan (from 1991), year-end charts were calculated by an inverse-point system based solely on a title's performance (for example a single appearing on the Billboard Hot 100 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. The same method was used for albums based on the Billboard 200, and songs appearing on the other charts (e.g., Hot Country Singles).