| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 8 |
0.8%
|
| 0 | No obstacle | 733 |
71.6%
|
| 1 | Minor obstacle | 145 |
14.2%
|
| 2 | Moderate obstacle | 66 |
6.4%
|
| 3 | Major obstacle | 57 |
5.6%
|
| 4 | Very severe obstacle | 15 |
1.5%
|