| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.4%
|
| -7 | Does not apply | 27 |
1.6%
|
| 0 | No obstacle | 311 |
18.7%
|
| 1 | Minor obstacle | 272 |
16.4%
|
| 2 | Moderate obstacle | 685 |
41.2%
|
| 3 | Major obstacle | 291 |
17.5%
|
| 4 | Very severe obstacle | 70 |
4.2%
|