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: Benjamin Thompson was a Loyalist during the American Revolution, and fled the country in 1775 when the British evacuated Boston. He returned late in the Rev War commanding the King's American Dragoons, who saw action in the Southern states. He returned to England after the British surrender. He eventually settled for a time in the Holy Roman Empire, where he acquired the title of Count Rumford, and where he performed his groundbreaking research into the design of heating systems. This research resulted in a series of improvements to home heating systems, notably the Rumford stove, a shallow fireplace that more efficiently projected heat into a room than older and larger fireplaces. While in Munich, Thompson oversaw reforms of the indigent welfare system of Bavaria, and designed the city's famous English Garden. Thompson was also an inveterate and practical tinkerer, developing new versions of everyday utensils. He also proposed in 1799 the establishment in the United Kingdom of a research organization, which resulted in the founding of the Royal Institution. Although he never returned to the country of his birth, he did endow a professorial chair at Harvard College, and established the Rumford Prize, an annual award given by the American Academy of Arts and Sciences. He died in Paris in 1814.
 Link Information: The American Revolution was a colonial revolt which occurred between 1765 and 1783.  Answer: 10
Solution:
How many years had the American Revolution been ongoing when the British evacuated Boston?