| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
0.8%
|
| -7 | Does not apply | 17 |
1.3%
|
| 0 | No obstacle | 401 |
30%
|
| 1 | Minor obstacle | 280 |
20.9%
|
| 2 | Moderate obstacle | 328 |
24.5%
|
| 3 | Major obstacle | 193 |
14.4%
|
| 4 | Very severe obstacle | 107 |
8%
|