| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.1%
|
| -7 | Does not apply | 158 |
15.8%
|
| 0 | No obstacle | 631 |
63.2%
|
| 1 | Minor obstacle | 167 |
16.7%
|
| 2 | Moderate obstacle | 30 |
3%
|
| 3 | Major obstacle | 11 |
1.1%
|
| 4 | Very severe obstacle | 0 |
0%
|