What was the average rate of change in the number of electric vehicles in use from 2001 to $2010 ?$
Do you think this model can be used for years before 2001 or after 2010 ? Explain your reasoning (Hint: use numbers to make your argument convincing)

Step 1 ：We are given the number of electric vehicles in use in 2001 and 2010. The number of electric vehicles in use in 2001 is 50000 and in 2010 is 200000.

Step 2 ：The average rate of change is calculated by subtracting the initial value from the final value and then dividing by the number of years. The formula for average rate of change is \(\frac{{final\ value - initial\ value}}{{final\ year - initial\ year}}\).

Step 3 ：Substitute the given values into the formula: \(\frac{{200000 - 50000}}{{2010 - 2001}}\).

Step 4 ：Simplify the expression to get the average rate of change: \(\frac{{150000}}{{9}}\) = 16666.666666666668.

Step 5 ：Round the result to two decimal places to get the final answer: \(\boxed{16666.67}\) vehicles per year.