| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 5 |
0.8%
|
| 0 | No obstacle | 177 |
29.5%
|
| 1 | Minor obstacle | 189 |
31.4%
|
| 2 | Moderate obstacle | 94 |
15.6%
|
| 3 | Major obstacle | 106 |
17.6%
|
| 4 | Very severe obstacle | 30 |
5%
|