Answer
$\approx 1,202,000$ households/year
Work Step by Step
We are given the function:
$N(x)=-0.023(x-33.12)^2+131$, $0\leq t\leq 14$
Find the average rate of change of the function from 2000 to 2014, that is from $t=0$ to $t=14$:
$\dfrac{N(14)-N(0)}{14-0}=\dfrac{[-0.023(14-33.12)^2+131]-[-0.023(0-33.12)^2+131]}{14}=\dfrac{122.592-105.771}{14}=\dfrac{16.821}{14}\approx 1.202$
This means that the number of households increased by an average of 1,202,000 each year from 2000 to 2014.