| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 4 |
1.1%
|
| 0 | No obstacle | 135 |
37.5%
|
| 1 | Minor obstacle | 100 |
27.8%
|
| 2 | Moderate obstacle | 77 |
21.4%
|
| 3 | Major obstacle | 34 |
9.4%
|
| 4 | Very severe obstacle | 9 |
2.5%
|