Cullumber Corporation produces microwave units. The following per-unit cost information is available: direct materials $34; direct labour $23; variable manufacturing overhead $20; fixed manufacturing overhead $43; variable selling and administrative expenses $13; and fixed selling and administrative expenses $29. Its desired ROI per unit is $28. 80. Calculate the markup percentage using variable-cost pricing. (Round answer to 2 decimal places, es. 15.25\%)