| Level | Cases (n = 236) | % |
| 0 | 18 | 7.6 |
| 1 | 28 | 11.9 |
| 2 | 16 | 6.8 |
| 3a | 44 | 18.6 |
| 3b | 94 | 39.8 |
| 4a | 1 | 0.4 |
| 4b | 6 | 2.5 |
| 5 | 15 | 6.4 |
| Others | 14 | 5.9 |
| ≥Level 3b | 116 | 49.2 |