Given the task definition, example input & output, solve the new input case.
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Example: Passage: In 1763, Spain traded Florida to the Kingdom of Great Britain for control of Havana, Cuba, which had been captured by the British during the Seven Years' War. It was part of a large expansion of British territory following the country's victory in the Seven Years' War. Almost the entire Spanish population left, taking along most of the remaining indigenous population to Cuba. The British soon constructed the King's Road connecting St. Augustine to Georgia. The road crossed the St. Johns River at a narrow point, which the Seminole called Wacca Pilatka and the British named "Cow Ford", both names ostensibly reflecting the fact that cattle were brought across the river there.
Output: Who owned Cuba after the Eight Years War?
This question appears to be relevant to the passage as both involves words such as 'Cuba' and 'War' which also exist in the passage. The passage mentions that "after the war, almost the entire Spanish population left, taking along most of the remaining indigenous population to Cuba". This information is not sufficient to conclude that which country owned cuba.

New input case for you: Passage: Following a peak in growth in 1979, the Liberian economy began a steady decline due to economic mismanagement following the 1980 coup. This decline was accelerated by the outbreak of civil war in 1989; GDP was reduced by an estimated 90% between 1989 and 1995, one of the fastest declines in history. Upon the end of the war in 2003, GDP growth began to accelerate, reaching 9.4% in 2007. The global financial crisis slowed GDP growth to 4.6% in 2009, though a strengthening agricultural sector led by rubber and timber exports increased growth to 5.1% in 2010 and an expected 7.3% in 2011, making the economy one of the 20 fastest growing in the world.
Output:
When did the Liberian economy reach peak timber exports?