A flexible asphalt pavement is designed with 4 inches of sand-mix asphalt wearing surface, 6 inches of dense-graded crushed stone base, and 8 inches of crushed stone subbase. All drainage coefficients are 1.0. The pavement is designed for 18-kip single-axle loads (1290 per day). The initial PSI is 4.5 and the TSI is 2.5. The soil has a resilient modulus of 12,000 lb/in2. If the overall standard deviation is 0.40, what is the probability that this pavement will have a PSI greater than 2.5 after 20 years