| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.3%
|
| 0 | No obstacle | 184 |
16.8%
|
| 1 | Minor obstacle | 187 |
17.1%
|
| 2 | Moderate obstacle | 149 |
13.6%
|
| 3 | Major obstacle | 233 |
21.3%
|
| 4 | Very severe obstacle | 340 |
31%
|