| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 172 |
28.5%
|
| 1 | Minor obstacle | 162 |
26.9%
|
| 2 | Moderate obstacle | 104 |
17.2%
|
| 3 | Major obstacle | 114 |
18.9%
|
| 4 | Very severe obstacle | 50 |
8.3%
|