A sample consisting of Na₂CO₃ and NaHCO₃, and inert matter weighs 6.6992 grams. It is titrated with 0.11 N HCl with phenolphthalein as the indicator, and the solution became colorless after the addition of 21.60 mL. Another duplicate sample was titrated with HCl using methyl orange as indicator. It required 59.53 mL of the acid for the color change. What is the percentage of NaHCO₃ (84g/mole) in the sample? (Answers should be written in 2 decimals place and do not include the UNIT)