A half-century ago, the mean height of women in a particular country in their 20s was 64.2 inches. Assume that the heights of today's women in their 20s are approximately normally distributed with a standard deviation of 1.85 inches. If the mean height today is the same as that of a half-century ago, what percentage of all samples of 20 of today's women in their 20s have mean heights of at least 65.33 inches?