| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 30 |
3.3%
|
| 0 | No obstacle | 318 |
34.6%
|
| 1 | Minor obstacle | 237 |
25.8%
|
| 2 | Moderate obstacle | 223 |
24.3%
|
| 3 | Major obstacle | 67 |
7.3%
|
| 4 | Very severe obstacle | 44 |
4.8%
|