| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.3%
|
| -7 | Does not apply | 56 |
5.5%
|
| 0 | No obstacle | 353 |
34.4%
|
| 1 | Minor obstacle | 173 |
16.9%
|
| 2 | Moderate obstacle | 190 |
18.5%
|
| 3 | Major obstacle | 204 |
19.9%
|
| 4 | Very severe obstacle | 46 |
4.5%
|