| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.3%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 68 |
11.1%
|
| 1 | Minor obstacle | 83 |
13.5%
|
| 2 | Moderate obstacle | 169 |
27.5%
|
| 3 | Major obstacle | 165 |
26.8%
|
| 4 | Very severe obstacle | 128 |
20.8%
|