| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.3%
|
| -7 | Does not apply | 77 |
5.1%
|
| 0 | No obstacle | 703 |
46.3%
|
| 1 | Minor obstacle | 226 |
14.9%
|
| 2 | Moderate obstacle | 356 |
23.5%
|
| 3 | Major obstacle | 108 |
7.1%
|
| 4 | Very severe obstacle | 44 |
2.9%
|