| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.9%
|
| -7 | Does not apply | 10 |
4.3%
|
| 0 | No obstacle | 185 |
79.4%
|
| 1 | Minor obstacle | 17 |
7.3%
|
| 2 | Moderate obstacle | 13 |
5.6%
|
| 3 | Major obstacle | 5 |
2.1%
|
| 4 | Very severe obstacle | 1 |
0.4%
|