| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 21 |
1.6%
|
| -7 | Does not apply | 38 |
2.9%
|
| 0 | No obstacle | 555 |
42%
|
| 1 | Minor obstacle | 359 |
27.1%
|
| 2 | Moderate obstacle | 226 |
17.1%
|
| 3 | Major obstacle | 48 |
3.6%
|
| 4 | Very severe obstacle | 76 |
5.7%
|