| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 129 |
32.9%
|
| 1 | Minor obstacle | 148 |
37.8%
|
| 2 | Moderate obstacle | 89 |
22.7%
|
| 3 | Major obstacle | 24 |
6.1%
|
| 4 | Very severe obstacle | 1 |
0.3%
|