| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
3%
|
| -7 | Does not apply | 57 |
9.5%
|
| 0 | No obstacle | 153 |
25.6%
|
| 1 | Minor obstacle | 186 |
31.1%
|
| 2 | Moderate obstacle | 152 |
25.4%
|
| 3 | Major obstacle | 21 |
3.5%
|
| 4 | Very severe obstacle | 11 |
1.8%
|