| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.7%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 366 |
51.3%
|
| 1 | Minor obstacle | 214 |
30%
|
| 2 | Moderate obstacle | 69 |
9.7%
|
| 3 | Major obstacle | 38 |
5.3%
|
| 4 | Very severe obstacle | 21 |
2.9%
|