| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.3%
|
| -7 | Does not apply | 2 |
0.7%
|
| 0 | No obstacle | 76 |
24.8%
|
| 1 | Minor obstacle | 88 |
28.7%
|
| 2 | Moderate obstacle | 50 |
16.3%
|
| 3 | Major obstacle | 62 |
20.2%
|
| 4 | Very severe obstacle | 25 |
8.1%
|