| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
0.8%
|
| -7 | Does not apply | 8 |
0.6%
|
| 0 | No obstacle | 321 |
23.4%
|
| 1 | Minor obstacle | 334 |
24.4%
|
| 2 | Moderate obstacle | 393 |
28.7%
|
| 3 | Major obstacle | 230 |
16.8%
|
| 4 | Very severe obstacle | 72 |
5.3%
|