Question: What year was the backing vocalist for Slipknot born?

Context paragraphs:
Slipknot discography: American heavy metal band Slipknot has released five studio albums, one live album, one compilation album, one demo album, 17 singles, four video albums and 23 music videos. Formed in Des Moines, Iowa in 1995, Slipknot originally featured vocalist and percussionist Anders Colsefni, guitarists Donnie Steele and Josh "Gnar" Brainard, bassist Paul Gray, drummer Joey Jordison, and percussionist and backing vocalist Shawn "Clown" Crahan.  The original lineup released its first demo "Mate.  Feed.  Kill.  Repeat. " in 1996, before undergoing a number of lineup changes over the next few years.

Sum 41: Sum 41 is a Canadian rock band from Ajax, Ontario.  Originally called Kaspir, the band formed in 1996 and currently consists of lead vocalist/rhythm guitarist/keyboardist Deryck Whibley, lead guitarist/backing vocalist Dave Baksh, rhythm/lead guitarist/keyboardist/backing vocalist Tom Thacker, bassist/backing vocalist Jason McCaslin and drummer Frank Zummo.

Marianas Trench (band): Marianas Trench is a Canadian pop punk band from Vancouver, British Columbia, formed in 2001.  The band consists of members Josh Ramsay (lead vocalist, rhythm guitarist, pianist, songwriter, and occasional drummer), Matt Webb (lead guitarist and backing vocalist), Mike Ayley (bass guitarist and backing vocalist), and Ian Casselman (drummer, percussionist, and backing vocalist).  The band has released four full-length studio albums, the most recent titled "Astoria", released on October 23, 2015, along with 2011's "Ever After", 2009's "Masterpiece Theatre" and 2006's "Fix Me".  Their third album "Ever After" was nominated for a Juno Award.

All Time Low: All Time Low is an American rock band from Towson, Maryland, a suburb of Baltimore, formed in 2003.  The band currently consists of lead vocalist and rhythm guitarist Alex Gaskarth, lead guitarist and backing vocalist Jack Barakat, bassist and backing vocalist Zack Merrick and drummer Rian Dawson.  The band's name is taken from lyrics in the song "Head on Collision" by New Found Glory.  The band consistently tours year-long, has headlined numerous tours, and has appeared at music festivals including Warped Tour, Reading and Leeds and Soundwave.

Shawn Crahan: Michael Shawn Crahan (born September 24, 1969), more commonly known by his stage persona "Clown", is an American musician, songwriter, record producer, director and photographer.  He is best known as one of the two custom percussionists and co-founder of the Grammy Award-winning heavy metal band Slipknot.  When performing with Slipknot, he is also known by his number 6.  Crahan is the only remaining founding member in Slipknot.

Lost Society: Lost Society is a Finnish four-piece thrash metal band formed in Jyväskylä, Finland in 2010.  The band consists of guitarist and lead vocalist Samy Elbanna, guitarist and backing vocalist Arttu Lesonen, bassist and backing vocalist Mirko Lehtinen, and drummer Ossi Paananen.

Justin Shekoski: Justin Paulhollis Shekoski (born June 11, 1983) is an American guitarist, songwriter, and vocalist, best known for being the former lead guitarist and backing vocalist of Saosin and the current guitarist and backing vocalist of The Used.  He has cited guitarists John Petrucci and Paul Gilbert as some of his main inspirations.  Shekoski also teaches guitar lessons in Orange County, California where he resides.

Angels &amp; Airwaves: Angels & Airwaves is an American rock supergroup, featuring Tom DeLonge (lead vocalist, keyboardist, bassist and guitarist) and Ilan Rubin (drummer, keyboardist, guitarist, bassist and backing vocalist).  Former members are Ryan Sinn (bassist and backing vocalist), Adam "Atom" Willard (drummer), Matt Wachter (bassist, keyboardist and backing vocalist).  The status of David Kennedy (guitarist and keyboardist) and Eddie Breckenridge (bassist) is currently unknown.

Avenged Sevenfold: Avenged Sevenfold (sometimes abbreviated as A7X) is an American heavy metal band from Huntington Beach, California, formed in 1999.  The band's current lineup consists of lead vocalist M. Shadows, rhythm guitarist and backing vocalist Zacky Vengeance, lead guitarist and backing vocalist Synyster Gates, bassist and backing vocalist Johnny Christ, and drummer Brooks Wackerman.

HubbaBubbas: HubbaBubbas is a Singaporean post-acoustic trio, founded in June 2011, consisting of lead vocalist Stephanie Lim, guitarist/backing vocalist Ryan Chan and beatboxer/backing vocalist Mervyn Ye.  They are one of Singapore's rising bands, known for combining various genres of music, and having performed at various local and international events.

Supporting paragraphs: Slipknot discography Shawn Crahan
Answer: 1969