| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 10 |
1%
|
| 0 | No obstacle | 345 |
34.5%
|
| 1 | Minor obstacle | 308 |
30.8%
|
| 2 | Moderate obstacle | 166 |
16.6%
|
| 3 | Major obstacle | 147 |
14.7%
|
| 4 | Very severe obstacle | 21 |
2.1%
|