| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 84 |
2.8%
|
| -7 | Does not apply | 62 |
2.1%
|
| 0 | No obstacle | 1288 |
43.6%
|
| 1 | Minor obstacle | 868 |
29.4%
|
| 2 | Moderate obstacle | 467 |
15.8%
|
| 3 | Major obstacle | 162 |
5.5%
|
| 4 | Very severe obstacle | 24 |
0.8%
|