| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.8%
|
| -7 | Does not apply | 11 |
1.8%
|
| 0 | No obstacle | 403 |
67.4%
|
| 1 | Minor obstacle | 132 |
22.1%
|
| 2 | Moderate obstacle | 33 |
5.5%
|
| 3 | Major obstacle | 6 |
1%
|
| 4 | Very severe obstacle | 8 |
1.3%
|