| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.7%
|
| -7 | Does not apply | 5 |
0.8%
|
| 0 | No obstacle | 318 |
52.2%
|
| 1 | Minor obstacle | 133 |
21.8%
|
| 2 | Moderate obstacle | 103 |
16.9%
|
| 3 | Major obstacle | 38 |
6.2%
|
| 4 | Very severe obstacle | 8 |
1.3%
|