| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 340 |
71.7%
|
| 1 | Minor obstacle | 72 |
15.2%
|
| 2 | Moderate obstacle | 42 |
8.9%
|
| 3 | Major obstacle | 12 |
2.5%
|
| 4 | Very severe obstacle | 8 |
1.7%
|