#### Answer

a. 8%
b. Between 2005 and 2006.
c. 2004

#### Work Step by Step

a.
The point on the axis representing the percentage in 2001 looks to be a bit after the middle between $5\%$ and $10\%$, so we can estimate that it's $\approx 8\%$.
b.
To see between which two years the percentage increased at the greatest rate, we don't need to estimate the value for each point and calculate the difference between them. We simply need to see between which two years the slope is the steepest and heading upwards.
We can see that the steepest slope in the graph is between the years 2005 and 2006; therefore, the percentage decreased the most between 2005 and 2006.
c.
Looking at the points on the graph for each year and their distance from the dotted line for $10\%$, we can see that the only point that could be at $12\%$ is 2004.