| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 28 |
2.1%
|
| -7 | Does not apply | 56 |
4.2%
|
| 0 | No obstacle | 355 |
26.6%
|
| 1 | Minor obstacle | 158 |
11.8%
|
| 2 | Moderate obstacle | 192 |
14.4%
|
| 3 | Major obstacle | 269 |
20.1%
|
| 4 | Very severe obstacle | 279 |
20.9%
|