The following graph shows the approximate value $V(t)$ of subprime $($normally classified as risky$)$ mortgage debt outstanding in the United States.

Use the graph to estimate, to one decimal place, the average rate of change of $V(t)$ with respect to $t$ over the interval $0,4$ and interpret the result.

The average rate of change is years $$ ans $2.$ which means that the subprime mortgage debt outstanding was $$ increasing $v$ at an average rate of around $$

billions of dollars per year $$

between the