| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1.3%
|
| -7 | Does not apply | 1 |
0.7%
|
| 0 | No obstacle | 32 |
21.2%
|
| 1 | Minor obstacle | 18 |
11.9%
|
| 2 | Moderate obstacle | 45 |
29.8%
|
| 3 | Major obstacle | 30 |
19.9%
|
| 4 | Very severe obstacle | 23 |
15.2%
|