| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1.3%
|
| -7 | Does not apply | 1 |
0.6%
|
| 0 | No obstacle | 25 |
15.9%
|
| 1 | Minor obstacle | 48 |
30.6%
|
| 2 | Moderate obstacle | 38 |
24.2%
|
| 3 | Major obstacle | 32 |
20.4%
|
| 4 | Very severe obstacle | 11 |
7%
|