| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1%
|
| -7 | Does not apply | 4 |
1.9%
|
| 0 | No obstacle | 16 |
7.7%
|
| 1 | Minor obstacle | 60 |
28.7%
|
| 2 | Moderate obstacle | 19 |
9.1%
|
| 3 | Major obstacle | 72 |
34.4%
|
| 4 | Very severe obstacle | 36 |
17.2%
|