Horn Company is considering the purchase of a new machine for $128,000. The machine would replace an old piece of equipment that costs $41,860 per year to operate. The new machine would cost $16,140 per year to operate. The old machine currently in use can be sold for $6,000 if the new machine is purchased. The new machine would have a useful life of ten years with a $5,000 salvage value. 

Calculate the accounting rate of return on the machine that Horn Company is considering buying. Enter your answer as a number followed by the percentage symbol with no spaces in between (i.e., 29%).