| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 15 |
6.2%
|
| -7 | Does not apply | 1 |
0.4%
|
| 0 | No obstacle | 140 |
57.9%
|
| 1 | Minor obstacle | 48 |
19.8%
|
| 2 | Moderate obstacle | 21 |
8.7%
|
| 3 | Major obstacle | 14 |
5.8%
|
| 4 | Very severe obstacle | 3 |
1.2%
|