| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 14 |
1%
|
| -7 | Does not apply | 34 |
2.5%
|
| 0 | No obstacle | 604 |
44.1%
|
| 1 | Minor obstacle | 312 |
22.8%
|
| 2 | Moderate obstacle | 207 |
15.1%
|
| 3 | Major obstacle | 143 |
10.4%
|
| 4 | Very severe obstacle | 55 |
4%
|