A circular water tank of $2\:m$ diameter has a circular orifice of diameter $0.1\:m$ at the bottom. Water enters the tank steadily at a flow rate of $20\:litre/s$ and escapes through the orifice. The coefficient of discharge of the orifice is $0.8$. Consider the acceleration due to gravity as $9.81\:m/s^2$ and neglect frictional losses. The height of the water level (in $m$, round off to two decimal places) in the tank at the steady state, is ______.