| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.3%
|
| -7 | Does not apply | 50 |
8.2%
|
| 0 | No obstacle | 271 |
44.3%
|
| 1 | Minor obstacle | 97 |
15.8%
|
| 2 | Moderate obstacle | 86 |
14.1%
|
| 3 | Major obstacle | 60 |
9.8%
|
| 4 | Very severe obstacle | 46 |
7.5%
|