Table 3

Perforations in each age category

Age (y) Group A Group B Total
0–4 9/11 (82%) 9/11 (82%)
4–8 5/12 (42%)15/21 (71%)20/33 (61%)
>8 7/39 (18%)31/46 (67%)38/85 (45%)
Total12/51 (24%)55/78 (71%)67/129 (52%)