| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 22 |
2%
|
| -7 | Does not apply | 20 |
1.8%
|
| 0 | No obstacle | 129 |
11.8%
|
| 1 | Minor obstacle | 273 |
24.9%
|
| 2 | Moderate obstacle | 407 |
37.1%
|
| 3 | Major obstacle | 217 |
19.8%
|
| 4 | Very severe obstacle | 28 |
2.6%
|