| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 8 |
0.8%
|
| 0 | No obstacle | 79 |
8.2%
|
| 1 | Minor obstacle | 63 |
6.5%
|
| 2 | Moderate obstacle | 271 |
28.1%
|
| 3 | Major obstacle | 344 |
35.6%
|
| 4 | Very severe obstacle | 201 |
20.8%
|