Figure 5. Results of the inter-class analysis. In males, there were significant inter-class effects between the 20-24 age group and the 25-29 age group, the 30-34 and the 35-39 age groups, the 40-44 and the 45-49 age group, and all age groups over 50 years. In females, significant inter-class effects were found between the 20-24 and the 25-29 age groups, and all age groups over 35 years. * indicates a significant difference from the preceding (i.e. younger) class.