| Age group (yrs) | Frequency | Percentage |
| 31 - 40 | 2 | 3.3 |
| 41 - 50 | 6 | 10.0 |
| 51 - 60 | 22 | 36.7 |
| 61 - 70 | 25 | 41.7 |
| 71 - 80 | 5 | 8.3 |
| Total | 60 | 100.0 |