Steam reforming of methane $($CH$4)$ produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. An industrial chemist studying this reaction fills a $125$L tank with $8\mathrm{.}9$ mol of methane gas and $\mathrm{.}25$ mol of water vapor, and when the mixture has come to equilibrium measures the amount of carbon monoxide gas to be $1\mathrm{.}8$ mol $.$ Calculate the concentration equilibrium constant for the steam reforming of methane at the final temperature of the mixture. Round your answer to significant $2$ digits.