| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
2%
|
| -7 | Does not apply | 1 |
0.7%
|
| 0 | No obstacle | 37 |
24.5%
|
| 1 | Minor obstacle | 27 |
17.9%
|
| 2 | Moderate obstacle | 54 |
35.8%
|
| 3 | Major obstacle | 18 |
11.9%
|
| 4 | Very severe obstacle | 11 |
7.3%
|