An aqueous suspension at $60^{\circ}C$ is fed to the first effect of a double effect forward feed evaporator with a mass flow rate of $1.25 \: kg \: s^{-1}$. The sum of the rates of water evaporated from the first and second effects is $1.0 \: kg \: s^{-1}$. Temperatures of the exit streams from the first and second effects are $100^{\circ}C$, and $60^{\circ}C$, respectively. Consider the specific heat of the aqueous suspension, and the latent heat of phase change for water to be $4 \: kJ \: kg^{-1} K^{-1}$ and $2200 \: kJ \: kg^{-1}$, respectively, over this temperature range. The steam economy (in $kg$ per $kg$) is ____________ (round off to $2$ decimal places).