2. The population of North Americans aged 55 and over as a percentage of the total population is approximated by the function:

f(x)=40(4x+100.30)) (0?x?20)(0?x?20)

Where x is measured in years and x = 0 corresponds to the year 2000.

For what reason did the percentage of Americans aged 55 and over change at the beginning of 2000?

For what reason did the percentage of Americans with 55 or more change at the beginning of 2010?

What is the percentage of Americans aged 55 and over in 2010?