| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 14 |
0.9%
|
| -7 | Does not apply | 209 |
13.8%
|
| 0 | No obstacle | 508 |
33.5%
|
| 1 | Minor obstacle | 219 |
14.4%
|
| 2 | Moderate obstacle | 454 |
29.9%
|
| 3 | Major obstacle | 95 |
6.3%
|
| 4 | Very severe obstacle | 19 |
1.3%
|