A 2.00 g portion of a sample containing NaBr and was dissolved and diluted to 250 mL. One fifth aliquot portions were titrated by silver nitrate, an average of 42.5 mL solution being required for the aliquot portion. In standardization 1.00 mL is found to be equimolar to 0.0125 g KBr. Calculate percentage of Br in sample.