| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 76 |
24.9%
|
| 1 | Minor obstacle | 98 |
32.1%
|
| 2 | Moderate obstacle | 108 |
35.4%
|
| 3 | Major obstacle | 17 |
5.6%
|
| 4 | Very severe obstacle | 5 |
1.6%
|