| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 108 |
21.5%
|
| 1 | Minor obstacle | 126 |
25.1%
|
| 2 | Moderate obstacle | 184 |
36.7%
|
| 3 | Major obstacle | 70 |
13.9%
|
| 4 | Very severe obstacle | 13 |
2.6%
|