| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.7%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 148 |
14.8%
|
| 1 | Minor obstacle | 173 |
17.3%
|
| 2 | Moderate obstacle | 188 |
18.8%
|
| 3 | Major obstacle | 344 |
34.4%
|
| 4 | Very severe obstacle | 139 |
13.9%
|