| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1%
|
| -7 | Does not apply | 7 |
3.3%
|
| 0 | No obstacle | 66 |
31.6%
|
| 1 | Minor obstacle | 84 |
40.2%
|
| 2 | Moderate obstacle | 31 |
14.8%
|
| 3 | Major obstacle | 18 |
8.6%
|
| 4 | Very severe obstacle | 1 |
0.5%
|