| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 298 |
81%
|
| 1 | Minor obstacle | 36 |
9.8%
|
| 2 | Moderate obstacle | 19 |
5.2%
|
| 3 | Major obstacle | 5 |
1.4%
|
| 4 | Very severe obstacle | 7 |
1.9%
|