| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
0.8%
|
| -7 | Does not apply | 14 |
1%
|
| 0 | No obstacle | 86 |
6.4%
|
| 1 | Minor obstacle | 104 |
7.8%
|
| 2 | Moderate obstacle | 250 |
18.7%
|
| 3 | Major obstacle | 357 |
26.7%
|
| 4 | Very severe obstacle | 515 |
38.5%
|