$\"\"$

From the graph, the number of cameras on the y - axis and the number of years on the x - axis.

From the graph, the points are $\"\"$ .

Substitute the values of $\"\"$ in the rate of change formula $\"\"$ .

$\"\"$

$\"\"$ millions per year. $\"\"$

The average rate of change of the number of digital cameras sold from 1999 to 2003 is 11 millions per year.