| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 193 |
53%
|
| 1 | Minor obstacle | 68 |
18.7%
|
| 2 | Moderate obstacle | 52 |
14.3%
|
| 3 | Major obstacle | 37 |
10.2%
|
| 4 | Very severe obstacle | 13 |
3.6%
|