| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 135 |
25.4%
|
| 1 | Minor obstacle | 75 |
14.1%
|
| 2 | Moderate obstacle | 133 |
25%
|
| 3 | Major obstacle | 159 |
29.9%
|
| 4 | Very severe obstacle | 29 |
5.5%
|