| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 12 |
1.2%
|
| 0 | No obstacle | 239 |
23.3%
|
| 1 | Minor obstacle | 174 |
17%
|
| 2 | Moderate obstacle | 184 |
18%
|
| 3 | Major obstacle | 264 |
25.8%
|
| 4 | Very severe obstacle | 148 |
14.4%
|