| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 2 |
0.8%
|
| 0 | No obstacle | 123 |
51%
|
| 1 | Minor obstacle | 56 |
23.2%
|
| 2 | Moderate obstacle | 39 |
16.2%
|
| 3 | Major obstacle | 18 |
7.5%
|
| 4 | Very severe obstacle | 3 |
1.2%
|