A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ml of $\mathrm{CO}_2$ at $\mathrm{T}=$ 298.15 K and $\mathrm{p}=1$ bar. If molar volume of $\mathrm{CO}_2$ is 25.0 L under such condition, what is the percentage of sodium bicarbonate in each tablet? [Molar mass of $\mathrm{NaHCO}_3=84 \mathrm{~g} \mathrm{~mol}^{-1}$ ]