| Age (years) | Quantity | Relative frequencies (%) | Accumulated frequencies (%) |
| 17 | 1 | 2.3 | 2.3 |
| 18 | 8 | 18.6 | 20.9 |
| 19 | 4 | 9.3 | 30.2 |
| 20 | 18 | 41.9 | 72.1 |
| 21 | 12 | 27.9 | 100 |
| Total | 43 | 100 |