| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 |
0.7%
|
| -7 | Does not apply | 5 |
0.4%
|
| 0 | No obstacle | 466 |
35.8%
|
| 1 | Minor obstacle | 320 |
24.6%
|
| 2 | Moderate obstacle | 262 |
20.2%
|
| 3 | Major obstacle | 152 |
11.7%
|
| 4 | Very severe obstacle | 86 |
6.6%
|