| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.7%
|
| -7 | Does not apply | 2 |
1.3%
|
| 0 | No obstacle | 78 |
52%
|
| 1 | Minor obstacle | 41 |
27.3%
|
| 2 | Moderate obstacle | 12 |
8%
|
| 3 | Major obstacle | 9 |
6%
|
| 4 | Very severe obstacle | 7 |
4.7%
|