Schuman Corporation produces microwave units. The following per-unit cost information is available: direct materials $35; direct labour $22; variable manufacturing overhead $17; fixed manufacturing overhead $41; variable selling and administrative expenses $13; and fixed selling and administrative expenses $28. Its desired ROI per unit is $27.57. Calculate the markup percentage using variable-cost pricing. (Round answer to 2 decimal places, e.g. 15.25%.)