| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 2 |
0.7%
|
| 0 | No obstacle | 121 |
41.4%
|
| 1 | Minor obstacle | 95 |
32.5%
|
| 2 | Moderate obstacle | 60 |
20.5%
|
| 3 | Major obstacle | 10 |
3.4%
|
| 4 | Very severe obstacle | 3 |
1%
|