Task: Question Generation
Input (English): Passage: The Spanish engaged in a strategy of concentrating native populations in newly founded colonial towns, or reducciones . Native resistance to the new nucleated settlements took the form of the flight of the indigenous inhabitants into inaccessible regions such as the forest or joining neighbouring Maya groups that had not yet submitted to the Spanish. Those that remained behind in the reducciones often fell victim to contagious diseases. An example of the effect on populations of this strategy is the province of Acalan, which occupied an area spanning southern Campeche and eastern Tabasco. When Hernán Cortés passed through Acalan in 1525 he estimated the population size as at least 10,000. In 1553 the population was recorded at around 4,000. In 1557 the population was forcibly moved to Tixchel on the Gulf coast, so as to be more easily accessible to the Spanish authorities. In 1561 the Spanish recorded only 250 tribute-paying inhabitants of Tixchel, which probably had a total population of about 1,100. This indicates a 90% drop in population over a 36-year span. Some of the inhabitants had fled Tixchel for the forest, while others had succumbed to disease, malnutrition and inadequate housing in the Spanish reducción. Coastal reducciones, while convenient for Spanish administration, were vulnerable to pirate attacks; in the case of Tixchel, pirate attacks and contagious European diseases led to the eradication of the reducción town and the extinction of the Chontal Maya of Campeche. Among the Maya, ambush was a favoured tactic.
Output (English): How many years after Hernán Cortés passed through Acalan and estimated the population of at least 10,000 was the population recorded to be around 4000?