| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
1.1%
|
| -7 | Does not apply | 8 |
3%
|
| 0 | No obstacle | 135 |
50.4%
|
| 1 | Minor obstacle | 70 |
26.1%
|
| 2 | Moderate obstacle | 33 |
12.3%
|
| 3 | Major obstacle | 18 |
6.7%
|
| 4 | Very severe obstacle | 1 |
0.4%
|