| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
1.7%
|
| 0 | No obstacle | 225 |
63.6%
|
| 1 | Minor obstacle | 52 |
14.7%
|
| 2 | Moderate obstacle | 34 |
9.6%
|
| 3 | Major obstacle | 24 |
6.8%
|
| 4 | Very severe obstacle | 13 |
3.7%
|