| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 4 |
0.5%
|
| 0 | No obstacle | 224 |
26.4%
|
| 1 | Minor obstacle | 172 |
20.2%
|
| 2 | Moderate obstacle | 212 |
24.9%
|
| 3 | Major obstacle | 168 |
19.8%
|
| 4 | Very severe obstacle | 70 |
8.2%
|