| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 4 |
1.1%
|
| 0 | No obstacle | 114 |
31.9%
|
| 1 | Minor obstacle | 73 |
20.4%
|
| 2 | Moderate obstacle | 110 |
30.8%
|
| 3 | Major obstacle | 30 |
8.4%
|
| 4 | Very severe obstacle | 22 |
6.2%
|