| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 3 |
0.5%
|
| 0 | No obstacle | 174 |
29.1%
|
| 1 | Minor obstacle | 98 |
16.4%
|
| 2 | Moderate obstacle | 144 |
24.1%
|
| 3 | Major obstacle | 118 |
19.7%
|
| 4 | Very severe obstacle | 61 |
10.2%
|