| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.9%
|
| -7 | Does not apply | 2 |
0.9%
|
| 0 | No obstacle | 192 |
82.4%
|
| 1 | Minor obstacle | 22 |
9.4%
|
| 2 | Moderate obstacle | 13 |
5.6%
|
| 3 | Major obstacle | 2 |
0.9%
|
| 4 | Very severe obstacle | 0 |
0%
|