The ammonia ($NH_{3}$) oxidation process occurs over a catalyst as

$$4NH_{3}+5O_{2}\rightarrow 6H_{2}O+4NO$$

Air is supplied such that oxygen ($O_{2}$) is $20\%$ in excess of that required for complete conversion of $NH_{3}$. The mole fraction of $O_{2}$ in inlet gas mixture ($NH_{3}$+ air ) is _______________ (rounded off to third decimal place).