| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 5 |
0.8%
|
| 0 | No obstacle | 63 |
9.8%
|
| 1 | Minor obstacle | 134 |
20.8%
|
| 2 | Moderate obstacle | 263 |
40.8%
|
| 3 | Major obstacle | 127 |
19.7%
|
| 4 | Very severe obstacle | 53 |
8.2%
|