| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 14 |
1%
|
| -7 | Does not apply | 32 |
2.4%
|
| 0 | No obstacle | 216 |
16.2%
|
| 1 | Minor obstacle | 152 |
11.4%
|
| 2 | Moderate obstacle | 310 |
23.2%
|
| 3 | Major obstacle | 367 |
27.4%
|
| 4 | Very severe obstacle | 246 |
18.4%
|