| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.9%
|
| -7 | Does not apply | 22 |
6.3%
|
| 0 | No obstacle | 274 |
77.8%
|
| 1 | Minor obstacle | 21 |
6%
|
| 2 | Moderate obstacle | 17 |
4.8%
|
| 3 | Major obstacle | 8 |
2.3%
|
| 4 | Very severe obstacle | 7 |
2%
|