| Volume (cm3) | <10 | 21 - 30 | 81 - 90 | >100 | Total |
| Age (years) |
|
|
|
|
|
| 59 - 68 | 3 | 0 | 0 | 3 | 6 |
| 69 - 78 | 2 | 1 | 0 | 0 | 3 |
| 79 - 88 | 1 | 0 | 1 | 2 | 4 |
| 89 - 98 | 0 | 0 | 0 | 1 | 1 |