Assume you decide to hold a portfolio with 75% invested in the S&P 500 U.S. stock index and the remaining 25% in the MSCI Emerging Markets index. The expected return is 9.93% for the S&P 500 and 18.20% for the Emerging Markets index. The risk (standard deviation) is 16.21% for the S&P 500 and 33.11% for the Emerging Markets index. Covariance between the S&P 500 and the Emerging Markets index is 0.1. Compute portfolio standard deviation. (Round your answer to 2 decimal places. (e.g., 32.16))