A portfolio consists of 35 percent of Stock S and 65 percent of Stock T. Stock S is expected to return 15 percent if the economy booms, 10 percent if it is normal, and lose 19 percent if it is recessionary. Stock T will return 26 percent in a boom, 15 percent in a normal economy, and lose 40 percent in a recession. The probability of a boom is 5 percent and probability of a recession is 10 percent. What is the portfolio standard deviation?