<image>At a certain school, 20 boys from both the sixth and ninth grades were randomly selected to measure their height, and the frequency distribution histograms depicted in Figure 2 were produced. The values at the upper ends of the two dashed lines represent the average height of the 20 boys selected from each grade. Based on the information provided in the figure, fill in the blanks:

(1) The range of the group where the median height of the 20 boys selected from the sixth grade falls is ____ centimeters; the range of the group where the median height of the 20 boys selected from the ninth grade falls is ____ centimeters.
(2) Estimate the average height of the boys in the ninth grade at this school to be ____ centimeters higher than the average height of the boys in the sixth grade.
(3) Estimate the percentage of all the boys in both the sixth and ninth grades at this school whose height is not less than 153 centimeters and less than 163 centimeters to be ____.