| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.1%
|
| 0 | No obstacle | 377 |
26.3%
|
| 1 | Minor obstacle | 366 |
25.6%
|
| 2 | Moderate obstacle | 353 |
24.7%
|
| 3 | Major obstacle | 217 |
15.2%
|
| 4 | Very severe obstacle | 118 |
8.2%
|