| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 74 |
14.5%
|
| 1 | Minor obstacle | 190 |
37.2%
|
| 2 | Moderate obstacle | 94 |
18.4%
|
| 3 | Major obstacle | 140 |
27.4%
|
| 4 | Very severe obstacle | 12 |
2.3%
|