| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.4%
|
| -7 | Does not apply | 11 |
0.8%
|
| 0 | No obstacle | 479 |
36.2%
|
| 1 | Minor obstacle | 318 |
24%
|
| 2 | Moderate obstacle | 287 |
21.7%
|
| 3 | Major obstacle | 161 |
12.2%
|
| 4 | Very severe obstacle | 62 |
4.7%
|