| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 4 |
0.6%
|
| 0 | No obstacle | 235 |
36.2%
|
| 1 | Minor obstacle | 141 |
21.7%
|
| 2 | Moderate obstacle | 174 |
26.8%
|
| 3 | Major obstacle | 59 |
9.1%
|
| 4 | Very severe obstacle | 36 |
5.5%
|