| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.2%
|
| 0 | No obstacle | 329 |
33%
|
| 1 | Minor obstacle | 333 |
33.4%
|
| 2 | Moderate obstacle | 203 |
20.3%
|
| 3 | Major obstacle | 116 |
11.6%
|
| 4 | Very severe obstacle | 15 |
1.5%
|