| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 10 |
1%
|
| 0 | No obstacle | 596 |
60.9%
|
| 1 | Minor obstacle | 276 |
28.2%
|
| 2 | Moderate obstacle | 69 |
7%
|
| 3 | Major obstacle | 18 |
1.8%
|
| 4 | Very severe obstacle | 10 |
1%
|