Nail \& Hammer Shack purchased 237 table fans of a particular make. The unit cost was $28.50 and the regular selling price was $60.00 each. The store sold 131 of them at the regular selling price. During a sale, it sold another 57 of them at markdown of 23.00%. The remaining units were sold at an additional markdown of 15.00% on the original price. What is the net rate of markup based on total cost? % Round to two decimal places