| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 59 |
2%
|
| -7 | Does not apply | 62 |
2.1%
|
| 0 | No obstacle | 1552 |
52.5%
|
| 1 | Minor obstacle | 689 |
23.3%
|
| 2 | Moderate obstacle | 416 |
14.1%
|
| 3 | Major obstacle | 133 |
4.5%
|
| 4 | Very severe obstacle | 44 |
1.5%
|