| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.8%
|
| -7 | Does not apply | 16 |
2.7%
|
| 0 | No obstacle | 110 |
18.4%
|
| 1 | Minor obstacle | 155 |
25.9%
|
| 2 | Moderate obstacle | 147 |
24.6%
|
| 3 | Major obstacle | 142 |
23.7%
|
| 4 | Very severe obstacle | 23 |
3.8%
|