| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 138 |
38.3%
|
| 1 | Minor obstacle | 66 |
18.3%
|
| 2 | Moderate obstacle | 89 |
24.7%
|
| 3 | Major obstacle | 38 |
10.6%
|
| 4 | Very severe obstacle | 24 |
6.7%
|