Billboard 200 - Wikipedia
https://en.wikipedia.org/wiki/Billboard_200Billboard began an album chart in 1945. Initially only five positions long, the album chart was not published on a weekly basis, sometimes three to seven weeks passing before it was updated. A biweekly (though with a few gaps), 15-position Best-Selling Popular Albums chart appeared in 1955. With the increase in album salesas the early 1950s format wars stabilized into market dominance by 45 RPM singles and long-playing twelve-inch albums, with 78 RPM record and lon…