| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 |
1.1%
|
| -7 | Does not apply | 67 |
9.3%
|
| 0 | No obstacle | 269 |
37.2%
|
| 1 | Minor obstacle | 138 |
19.1%
|
| 2 | Moderate obstacle | 121 |
16.7%
|
| 3 | Major obstacle | 70 |
9.7%
|
| 4 | Very severe obstacle | 50 |
6.9%
|