| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1%
|
| -7 | Does not apply | 3 |
1.4%
|
| 0 | No obstacle | 70 |
33.5%
|
| 1 | Minor obstacle | 77 |
36.8%
|
| 2 | Moderate obstacle | 29 |
13.9%
|
| 3 | Major obstacle | 16 |
7.7%
|
| 4 | Very severe obstacle | 12 |
5.7%
|