| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 4 |
1.1%
|
| 0 | No obstacle | 261 |
72.5%
|
| 1 | Minor obstacle | 47 |
13.1%
|
| 2 | Moderate obstacle | 32 |
8.9%
|
| 3 | Major obstacle | 7 |
1.9%
|
| 4 | Very severe obstacle | 7 |
1.9%
|