The rate of return on Cherry Jalopies, Inc., stock over the last five years was 7 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?