Vaughn Inc. has completed the purchase of new Dell computers. The fair value of the equipment is $873,599. The purchase agreement specifies an immediate down payment of $212,000 and semiannual payments of $81,569 beginning at the end of 6 months for 5 years. What is the interest rate, to the nearest percent, used in discounting this purchase transaction? (Round factor values to 5 decimal places, e.g. 1,25124 and final answer to 0 decimal places, e.g. 25\%.) Interest rate % semi-annually