| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.7%
|
| -7 | Does not apply | 4 |
1%
|
| 0 | No obstacle | 151 |
36.9%
|
| 1 | Minor obstacle | 86 |
21%
|
| 2 | Moderate obstacle | 94 |
23%
|
| 3 | Major obstacle | 51 |
12.5%
|
| 4 | Very severe obstacle | 20 |
4.9%
|