[ Mathematics ] Open Question : Population growth quadratic model?

I have to make a quadratic graph modeling population growth. If I want to do between the years 2000-2005 of the population growth of the United States, how do I go about doing that? How do I even know if the information is quadratic? Please help!

Source: http://answers.yahoo.com/question/index?qid=20110314105919AAsPYXe

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