| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 41 |
3.1%
|
| -7 | Does not apply | 108 |
8.2%
|
| 0 | No obstacle | 470 |
35.5%
|
| 1 | Minor obstacle | 255 |
19.3%
|
| 2 | Moderate obstacle | 268 |
20.3%
|
| 3 | Major obstacle | 128 |
9.7%
|
| 4 | Very severe obstacle | 53 |
4%
|