| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.7%
|
| -7 | Does not apply | 8 |
1.3%
|
| 0 | No obstacle | 140 |
23.4%
|
| 1 | Minor obstacle | 153 |
25.6%
|
| 2 | Moderate obstacle | 148 |
24.7%
|
| 3 | Major obstacle | 123 |
20.6%
|
| 4 | Very severe obstacle | 22 |
3.7%
|