Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

As civil wars engulfed several Central American countries in the 1980s, hundreds of thousands of Salvadorans fled their country and came to the United States. Between 1980 and 1990, the Salvadoran immigrant population in the United States increased nearly fivefold from 94,000 to 465,000. The number of Salvadoran immigrants in the United States continued to grow in the 1990s and 2000s as a result of family reunification and new arrivals fleeing a series of natural disasters that hit El Salvador, including earthquakes and hurricanes. By 2008, there were about 1.1 million Salvadoran immigrants in the United States.
Why did Central Americans flee to the U.S.?