| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 39 |
3.1%
|
| -7 | Does not apply | 49 |
4%
|
| 0 | No obstacle | 1013 |
81.8%
|
| 1 | Minor obstacle | 49 |
4%
|
| 2 | Moderate obstacle | 48 |
3.9%
|
| 3 | Major obstacle | 23 |
1.9%
|
| 4 | Very severe obstacle | 18 |
1.5%
|