An active volcanic mountain grows in the shape of a cone while maintaining its base diameter equal to its height. The height of the mountain increases at a rate of $2$ feet per year.
**At what rate is the volume of the mountain increasing when the height is $3{,}000$ feet?**
Express your answer to the nearest tenth (i.e.$~0.1~$) of a cubic foot per year.
[Note: The volume of a cone is $\dfrac{\pi}{3}r^2h$, where $r$ is the radius of the base and $h$ is the height of the cone.]
$\qquad$[[☃ math-keypad 1]] $\dfrac{\text{feet}^3}{\text{year}}$
