| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 7 |
1.9%
|
| 0 | No obstacle | 189 |
52.4%
|
| 1 | Minor obstacle | 78 |
21.6%
|
| 2 | Moderate obstacle | 61 |
16.9%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 8 |
2.2%
|