reducing to 5 in the following weeks, and increasing again to 10 in 1948. The album chart was split into 33-8 and 45 rpm lists in 1950 before they recombined in 1954, then divided into mono and stereo classifications in 1959 before they merged into a 150-item pop album chart in 1963. It was eventually expanded into a 200 album list on May 13, 1967. Various genre album charts were also published: Country LP chart in January 1964, R&B chart in 1965, jazz in 1969, Latin in 1973, Gospel 1974, and Rock in 1981. Other charts include Classical albums, Comedy Albums, Holiday Albums, Soundtracks, Independent Albums, Catalog Album and many others besides. At the end of each year, Billboard tallies the results of all of its charts, and the results are published in a year-end issue and heard on year-end editions of its American Top 40 and American Country Countdown radio broadcasts. The first such annual charts released were for the year 1946, published on the January 4, 1947, issue, although annual listing of songs had been published irregularly some years prior, such as the undifferentiated annual chart based on "Honor Roll of Hits" for 1945. Between 1991 and 2006, the top single/album/artist(s) in each of those charts was/were awarded in the form of the annual Billboard Music Awards, which were held in December until the awards went dormant in 2007. The awards returned in May 2011. Chart compilation methodology For many years, a song had to be commercially available as a single to be considered for any of the Billboard charts. At the time, instead of using Nielsen SoundScan or Nielsen Broadcast Data Systems (BDS), Billboard obtained its data from manual reports filled out by radio stations and stores. For different musical genres, which stations and stores are used separates the charts; each musical genre has a core audience or retail group. Each genre's department at Billboard is headed up by a chart manager, who makes these determinations. According to the 50th-anniversary issue of Billboard, prior to the official implementation of SoundScan tracking in November 1991, many radio stations and retail stores removed songs from their manual reports after the associated record labels stopped promoting a particular single. Thus, songs fell quickly after peaking and had shorter chart lives. In 1990, the country singles chart was the first chart to use SoundScan and BDS. They were followed by the