| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 4 |
3.5%
|
| 0 | No obstacle | 69 |
60.5%
|
| 1 | Minor obstacle | 26 |
22.8%
|
| 2 | Moderate obstacle | 11 |
9.6%
|
| 3 | Major obstacle | 3 |
2.6%
|
| 4 | Very severe obstacle | 1 |
0.9%
|