A 2.0 g sample containing $\mathrm{MnO}_2$ is treated with HCl liberating $\mathrm{Cl}_2$. The $\mathrm{Cl}_2$.gas is passed into a solution of KI and 60.0 mL of 0.1 M $\mathrm{Na}_2 \mathrm{~S}_2 \mathrm{O}_3$ is required to titrate the liberated iodine. The percentage of $\mathrm{MnO}_2$ in the sample is __________. (Nearest integer) [Atomic masses (in u) Mn = 55; Cl = 35.5; O = 16, I = 127, Na = 23, K = 39, S = 32]