Social Security The total amount paid by the U.S. government to individual...

Social Security The total amount paid by the U.S. government to individuals for Social Security retirement and disability insurance benefits during the period 2000–2010 can be approximated by the linear model

y = 29.4x + 391.2.

where x = 0 corresponds to 2000, x = 1 corresponds to 2001, and so on. The variable y is in billions of dollars. Based on this model, during what year did the amount paid by the government first exceed $600 billion? Round your answer to the nearest year. Compare your answer to the bar graph.