| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.8%
|
| -7 | Does not apply | 20 |
3.4%
|
| 0 | No obstacle | 503 |
85%
|
| 1 | Minor obstacle | 18 |
3%
|
| 2 | Moderate obstacle | 25 |
4.2%
|
| 3 | Major obstacle | 13 |
2.2%
|
| 4 | Very severe obstacle | 8 |
1.4%
|