Albums Chart
Billboard began charting the bestselling albums in the U.S. in 1945. The chart was titled the Pop Albums chart beginning in the mid-1950's. In 1983 it was renamed the Billboard 200. The chart first included 200 positions in 1967.
Until 1991 the chart was compiled by written reports from record stores and other music retailers. In 1991 the chart began using Nielsen SoundScan data to compile the chart. Every time an album is sold from one of approximately 14,000 retailers in the U.S., that information is scanned and becomes part of the Billboard 200 chart. The chart published in Billboard magazine only indicates the ranking of an album's sales relative to other albums. It does not include data on the actual number of units sold. The data on number of units sold is only available directly from Nielsen.
In the 1990's Billboard made a significant change to its albums charts by adding the Top Pop Catalog Albums chart. In the past, the Billboard 200 tracked the sales of all albums regardless of how long they were in release. With the creation of the Top Pop Catalog Albums chart, any album which is more than 2 years old and has fallen out of the first 100 places of the Billboard 200 is permanently moved to the Top Pop Catalog Albums chart. Therefore, the Billboard 200 became specifically a chart of newer albums. It is unlikely now that any album will ever match Pink Floyd's record of 741 weeks (or about 14 years) on the Billboard 200 for Dark Side Of the Moon
