| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 23 |
2.3%
|
| -7 | Does not apply | 26 |
2.6%
|
| 0 | No obstacle | 605 |
60%
|
| 1 | Minor obstacle | 221 |
21.9%
|
| 2 | Moderate obstacle | 92 |
9.1%
|
| 3 | Major obstacle | 38 |
3.8%
|
| 4 | Very severe obstacle | 3 |
0.3%
|