Question: As a film editor, Jim Clark worked on the British biographical drama film, The Killing Fields, that was released when?

Context paragraphs:
George Clark (producer): George Clark (1888-1946) was a British film actor and film producer during the silent era.  For many years Clark worked with the British star Guy Newall, who he had met during the First World War.  Together they founded Lucky Cat Films and later George Clark Productions, securing a distribution arrangement with the larger Stoll Pictures.

The Killing Fields (film): The Killing Fields is a 1984 British biographical drama film about the Khmer Rouge regime in Cambodia, which is based on the experiences of two journalists: Cambodian Dith Pran and American Sydney Schanberg.  It was directed by Roland Joffé and produced by David Puttnam for his company Goldcrest Films.  Sam Waterston stars as Schanberg, Haing S. Ngor as Pran, Julian Sands as Jon Swain, and John Malkovich as Al Rockoff.  The adaptation for the screen was written by Bruce Robinson; the musical score was written by Mike Oldfield and orchestrated by David Bedford.

Creation (2009 film): Creation is a 2009 British biographical drama film about Charles Darwin's relationship with his wife Emma and his memory of their eldest daughter Annie, as he struggles to write "On the Origin of Species".  The film, directed by Jon Amiel and starring real life couple Paul Bettany and Jennifer Connelly as Charles and Emma Darwin, is a partly biographical, partly fictionalised account, based on Randal Keynes's Darwin biography "Annie's Box".

A Man for All Seasons (1966 film): A Man for All Seasons is a 1966 British biographical drama film in Technicolor based on Robert Bolt's play of the same name and adapted for the big screen by Bolt himself.  It was released on 12 December 1966.  It was directed by Fred Zinnemann, who had previously directed the films "High Noon" and "From Here to Eternity".

The Killing of John Lennon: The Killing of John Lennon is a 2006 British biographical drama film about Mark Chapman's plot to kill musician John Lennon.  The film was written and directed by Andrew Piddington, and stars Jonas Ball, Robert C. Kirk and Thomas A. McMahon.

Sri Lanka's Killing Fields: War Crimes Unpunished: Sri Lanka's Killing Fields: War Crimes Unpunished was an investigatory documentary about the final weeks of the Sri Lankan Civil War broadcast by the British TV station Channel 4 on 14 March 2012.  It was a sequel to the award-winning "Sri Lanka's Killing Fields" which was broadcast by Channel 4 in June 2011.  Made by film maker Callum Macrae, this documentary focused on four specific cases and investigated who was responsible for them.  Using amateur video from the conflict zone filmed by civilians and Sri Lankan soldiers, photographs and statements by civilians, soldiers and United Nations workers, the documentary traced ultimate responsibility for the cases to Sri Lanka's political and military leaders.  The documentary was made by ITN Productions and presented by Jon Snow, the main anchor on Channel 4 News.  The Sri Lankan government has denied all the allegations in the documentary.

The Killing Fields (album): The Killing Fields is the 10th record album by Mike Oldfield, released in 1984 on Virgin Records.  It was the soundtrack album for the British drama film of the same name based on the experiences of two journalists in the Khmer Rouge regime in Cambodia.  It is the only full-length film score written by Oldfield.

The Invisible Woman (2013 film): The Invisible Woman is a 2013 British biographical drama film directed by Ralph Fiennes and starring Fiennes, Felicity Jones, Kristin Scott Thomas and Tom Hollander.  Written by Abi Morgan, and based on the book "The Invisible Woman" by Claire Tomalin, the film is about the secret love affair between Charles Dickens and Nelly Ternan, which lasted for thirteen years until his death in 1870.  The film premiered at the Telluride Film Festival on 31 August 2013, and was released in the United Kingdom on 7 February 2014.  The film received a Best Costume Design nomination (Michael O'Connor) at the 86th Academy Awards.

A Street Cat Named Bob (film): A Street Cat Named Bob is a 2016 British biographical drama film directed by Roger Spottiswoode and written by Tim John and Maria Nation.  It is based on the book of same name by James Bowen.  The film stars Luke Treadaway, Ruta Gedmintas, Joanne Froggatt, Anthony Head and Bob the Cat as himself.  The film premiered in London on 3 November 2016, followed by a general release the next day.

Jim Clark (film editor): Jim Clark (24 May 1931 – 25 February 2016) was a British film editor with more than forty feature film credits from 1956–2008.  Clark has also directed eight features and short films.  Among his most recognized films are "Midnight Cowboy" (as creative consultant-1969), "Marathon Man" (1976), "The Killing Fields" (1984), and "Vera Drake" (2004).  In 2011, Clark published "Dream Repairman: Adventures in Film Editing", which is a memoir of his career.

Supporting paragraphs: Jim Clark (film editor) The Killing Fields (film)
Answer: 1984