| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.8%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 492 |
82%
|
| 1 | Minor obstacle | 80 |
13.3%
|
| 2 | Moderate obstacle | 17 |
2.8%
|
| 3 | Major obstacle | 5 |
0.8%
|
| 4 | Very severe obstacle | 1 |
0.2%
|