19. In a tire factory, the quality control inspector examines a randomly chosen sample of 15 tires. When more than one defective tire is found, production is halted, the existing tires are recycled, and production is then resumed. The purpose of this process is to ensure that the defect rate is no higher than 6%. Occasionally, by a stroke of bad luck, even if the defect rate is no higher than 6%, more than one defective tire occurs among the 15 chosen. Determine the fraction of the time that this happens.