| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | |
| -7 | Does not apply | 2 |
0.6%
|
| 0 | No obstacle | 161 |
44.7%
|
| 1 | Minor obstacle | 95 |
26.4%
|
| 2 | Moderate obstacle | 78 |
21.7%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 7 |
1.9%
|