| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 |
1.1%
|
| -7 | Does not apply | 14 |
1.8%
|
| 0 | No obstacle | 364 |
47.9%
|
| 1 | Minor obstacle | 125 |
16.4%
|
| 2 | Moderate obstacle | 149 |
19.6%
|
| 3 | Major obstacle | 78 |
10.3%
|
| 4 | Very severe obstacle | 22 |
2.9%
|