| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 13 |
3.6%
|
| 0 | No obstacle | 110 |
30.6%
|
| 1 | Minor obstacle | 49 |
13.6%
|
| 2 | Moderate obstacle | 70 |
19.4%
|
| 3 | Major obstacle | 64 |
17.8%
|
| 4 | Very severe obstacle | 50 |
13.9%
|