| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 2 |
0.5%
|
| 0 | No obstacle | 106 |
24.7%
|
| 1 | Minor obstacle | 117 |
27.3%
|
| 2 | Moderate obstacle | 162 |
37.8%
|
| 3 | Major obstacle | 36 |
8.4%
|
| 4 | Very severe obstacle | 5 |
1.2%
|