| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 28 |
2%
|
| -7 | Does not apply | 33 |
2.4%
|
| 0 | No obstacle | 309 |
22.6%
|
| 1 | Minor obstacle | 322 |
23.5%
|
| 2 | Moderate obstacle | 335 |
24.5%
|
| 3 | Major obstacle | 255 |
18.6%
|
| 4 | Very severe obstacle | 87 |
6.4%
|