| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 30 |
2.7%
|
| -7 | Does not apply | 42 |
3.8%
|
| 0 | No obstacle | 136 |
12.4%
|
| 1 | Minor obstacle | 259 |
23.6%
|
| 2 | Moderate obstacle | 399 |
36.4%
|
| 3 | Major obstacle | 207 |
18.9%
|
| 4 | Very severe obstacle | 23 |
2.1%
|