| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.8%
|
| -7 | Does not apply | 60 |
16.7%
|
| 0 | No obstacle | 163 |
45.3%
|
| 1 | Minor obstacle | 47 |
13.1%
|
| 2 | Moderate obstacle | 44 |
12.2%
|
| 3 | Major obstacle | 32 |
8.9%
|
| 4 | Very severe obstacle | 11 |
3.1%
|