The rectangle has vertices at $(-1, -1)$, $(-1, 3)$, $(2, 3)$, and $(2, -1)$.

The total area of the rectangle is:

$\text{width} \times \text{height} = 3 \times 4 = 12$

The portion in Quadrant IV is where $x > 0$ and $y < 0$. This region spans $x$ from $0$ to $2$ and $y$ from $-1$ to $0$:

$\text{Area in Q4} = 2 \times 1 = 2$

The percentage of the rectangle in Quadrant IV:

$\frac{2}{12} = \frac{1}{6} \approx 16\tfrac{2}{3}\%$