Over the past six years, a stock produced returns of 5.2, 18.1, 6.4, 10.2, 8.2, and 1.9 percent, respectively. For these same six years, the risk-free rate has been 2.4, 3.2, 1.8, 2.2, 4.8, and 1.8 percent, respectively. What's the arithmetic average risk premium on the stock for this time period?