The population density of a certain 750 square mile area in 1980 was 1253 people per square mile. In 1990, the population density was 1387 people per square mile. In 2000, the population density was 1405 people per square mile. In 2010, the population density was 1498 people per square mile.

a. What was the population of this area in 1980?
b. How much did the population change between 1980 and 2010?
c. Which decade had the smallest percentage increase in population?

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