| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 14 |
3.9%
|
| 0 | No obstacle | 142 |
39.3%
|
| 1 | Minor obstacle | 125 |
34.6%
|
| 2 | Moderate obstacle | 67 |
18.6%
|
| 3 | Major obstacle | 7 |
1.9%
|
| 4 | Very severe obstacle | 4 |
1.1%
|