Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
Problem:Passage: Stanford was commissioned into the Welsh Guards in 1987 and saw active service during the Troubles in Northern Ireland for which he was appointed a Member of the Order of the British Empire in October 1993. He went on to become commanding officer of 1st Battalion the Welsh Guards in which capacity he was deployed to Bosnia and Herzegovina on peace keeping duties in 2006. He was the Field Officer in Brigade Waiting and commanded the parade in Trooping the Colour 2007. In 2009 he was succeeded by Rupert Thorneloe just prior to the battalion's deployment to Afghanistan and the latter was killed in action during Operation Panther's Claw. He saw active service during the Iraq War when he served as an advisor to the Head of the Iraqi Army in 2009. He became Chief of Joint Fires and Influence Branch at Headquarters Allied Rapid Reaction Corps in March 2012 and General Officer Commanding Support Command in June 2015. He became Senior British Loan Services Officer, Oman in October 2017.
Link Information: The conflict began in the late 1960s and is usually deemed to have ended with the Good Friday Agreement of 1998. Answer: 20
Solution:
How long had the Troubles been going on when Standord joined the Welsh Guards?