| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.4%
|
| -7 | Does not apply | 30 |
1.7%
|
| 0 | No obstacle | 356 |
20.6%
|
| 1 | Minor obstacle | 360 |
20.9%
|
| 2 | Moderate obstacle | 408 |
23.7%
|
| 3 | Major obstacle | 370 |
21.4%
|
| 4 | Very severe obstacle | 194 |
11.2%
|