our firm is considering purchasing a machine with the following annual, end-of-year, book investment accounts. Year 0 Year 1 Year 2 Year 3 Year 4 Gross investment $ 66,000 $ 66,000 $ 66,000 $ 66,000 $ 66,000 Less: Accumulated depreciation 0 16,500 33,000 49,500 66,000 Net investment $ 66,000 $ 49,500 $ 33,000 $ 16,500 $ 0 The machine generates, on average, $5,100 per year in additional net income. What is the average accounting return for this machine? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)