Answer
The percent of pay raise is on average not changing during the years (staying at a constant 3%).
Work Step by Step
To calculate the average rate of change between two points $(x_1,y_1)$ and $(x_2,y_2)$, we use the formula:
$\displaystyle average~rate~of~change=\frac{y_2-y_1}{x_2-x_1}$
We calculate the average rate of change with the points $(0,3)$ and $(4,3)$:
average rate of change$=\frac{3-3}{4-0}=0$ percent of pay raise per year
Therefore, the percent of pay raise is on average not changing during the years (staying at a constant 3%).