Wells and Pumps

The total drawdown in a pumping well is given by Jacob's well loss equation: $s_w = B Q + C Q^2$, where $B = 0.0025\text{ day/m}^2$ is the aquifer loss coefficient and $C = 5.0 \times 10^{-7}\text{ day}^2/\text{m}^5$ is the well loss coefficient. The well is pumped at a steady discharge of $Q = 2000.0\text{ m}^3/\text{day}$. The well efficiency ($\eta_w = \frac{B Q}{s_w} \times 100\%$) in percent ($\text{\%}$) is ________ (round off to one decimal place).