| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 24 |
2.3%
|
| 0 | No obstacle | 734 |
71.7%
|
| 1 | Minor obstacle | 168 |
16.4%
|
| 2 | Moderate obstacle | 70 |
6.8%
|
| 3 | Major obstacle | 25 |
2.4%
|
| 4 | Very severe obstacle | 3 |
0.3%
|