| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.4%
|
| -7 | Does not apply | 15 |
2%
|
| 0 | No obstacle | 164 |
21.6%
|
| 1 | Minor obstacle | 149 |
19.6%
|
| 2 | Moderate obstacle | 280 |
36.8%
|
| 3 | Major obstacle | 117 |
15.4%
|
| 4 | Very severe obstacle | 32 |
4.2%
|