The rate of return on Cherry Jalopies, Inc., stock over the last five years was 17 percent, 21 percent, -8 percent, -5 percent, and 31 percent. Over the same period, the return on Straw Construction Company’s stock was 12 percent, 34 percent, -11 percent, -7 percent, and 41 percent. What was the arithmetic average return on each stock over this period?​