At $20^{\circ} \mathrm{C}$, the vapour pressure of benzene is 70 torr and that of methyl benzene is 20 torr. The mole fraction of benzene in the vapour phase at $20^{\circ} \mathrm{C}$ above an equimolar mixture of benzene and methyl benzene is
$\_\_\_\_$ $\times 10^{-2}$. (Nearest integer)
