| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 2 |
0.5%
|
| 0 | No obstacle | 138 |
37.9%
|
| 1 | Minor obstacle | 57 |
15.7%
|
| 2 | Moderate obstacle | 83 |
22.8%
|
| 3 | Major obstacle | 59 |
16.2%
|
| 4 | Very severe obstacle | 24 |
6.6%
|