| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 8 |
2.2%
|
| 0 | No obstacle | 229 |
63.8%
|
| 1 | Minor obstacle | 60 |
16.7%
|
| 2 | Moderate obstacle | 37 |
10.3%
|
| 3 | Major obstacle | 12 |
3.3%
|
| 4 | Very severe obstacle | 11 |
3.1%
|