| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 218 |
60.4%
|
| 1 | Minor obstacle | 57 |
15.8%
|
| 2 | Moderate obstacle | 63 |
17.5%
|
| 3 | Major obstacle | 15 |
4.2%
|
| 4 | Very severe obstacle | 5 |
1.4%
|