Question: Leader II is a 1991 studio album by a glam rock singer who sold over how many records?

Context paragraphs:
Dance Me Up: "Dance Me Up" is a song by English glam rock singer Gary Glitter, written by Glitter with Mike Leander and Eddie (Edward John) Seago and produced by Mike Leander.  It was released as the second single from his fifth studio album, "Boys Will Be Boys" (1984).  The single features the non-album track, "Too Young to Dance" as its B-side, which was exclusive to the single.

Leader II: Leader II is a 1991 studio album by English musician Gary Glitter.  It was his first album in seven years, 1984's "Boys Will Be Boys" being his previous album.  The album includes the single "Ready to Rock".

It Takes All Night Long: "It Takes All Night Long" is a song by English glam rock singer Gary Glitter, written by Glitter with Mike Leander and Eddie (Edward John) Seago and produced by Mike Leander.  It was released as the second single from his fourth studio album, "Silver Star" (1977), peaking at No. 25 on the UK Singles Chart.

Whatever Happened to Slade: Whatever Happened to Slade is the seventh studio album by the British rock group Slade.  It was released on 21 March 1977 by Barn Records, but did not enter any national album chart.  By the time of the album's release, Slade's popularity was waning as were their record sales, which they acknowledged in the album's title.  The glam rock movement, of which Slade were associated, had died, and the careers of other glam rock artists such as Mud, Gary Glitter and Sweet had also died.  In Britain, where Slade had traditionally been most popular, the fashion of the day was punk rock.  With this album, Slade firmly stood its ground as a straight rock group, and gone were their "glam" statements of the early decade.

Sensory Overdrive: Sensory Overdrive is the sixth studio album by the Finnish glam rock singer Michael Monroe, released on 14 March 2011 through Spinefarm Records.  It is Monroe's first studio album with his new backing band formed in early 2010, as well as his first studio solo album since the second break-up of his band Hanoi Rocks in 2009.

Whatcha Want: Whatcha Want is the fifth studio album by Finnish glam rock singer Michael Monroe, released on January 21, 2003, through the German label SPV GmbH.

Touch Me (Gary Glitter album): Touch Me is the second studio album by English glam rock singer Gary Glitter.  It was originally released in June 1973, on the label Bell.  It is Glitter's bestselling album, peaking at No. 2 on the UK Albums Chart.  It features the Top 5 hits "Do You Wanna Touch Me" and "Hello, Hello, I'm Back Again".

Peace of Mind (Michael Monroe album): Peace of Mind is the third studio album by Finnish glam rock singer Michael Monroe.  released in 1996.  The album was re-issued and made available worldwide on a widespread release only on March 14, 2000.

Another Rock and Roll Christmas: "Another Rock and Roll Christmas" is a Christmas song by English glam rock singer Gary Glitter, written by Glitter with Mike Leander and Eddie (Edward John) Seago and produced by Mike Leander.  It was one of the most played Christmas hits on UK radio from the mid-1980s to the mid-1990s, but is now rarely heard publicly following Glitter's convictions on child pornography and abuse charges.  Initially released in 1984, the song was later included on Glitter's fifth studio album, "Boys Will Be Boys" (1984) and was reissued many times, both as a single (including a collectors picture disc) and on other albums.

Gary Glitter: Paul Francis Gadd (born 8 May 1944), known by the stage name Gary Glitter, is an English former glam rock singer, who achieved popular success in the 1970s and 80s.  He was known for his extreme glam image of glitter suits, make-up and platform boots, and his energetic live performances.  He sold over 20 million records, spent 168 weeks on the UK Singles Chart and had 21 hit singles placing him in the Top 100 UK most successful chart acts.  From 1997, he returned to public notice for committing sex offences, being imprisoned for downloading child pornography in 1999, and child sexual abuse and attempted rape in 2006 and 2015.

Supporting paragraphs: Leader II Gary Glitter
Answer: 20 million