| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 36 |
1.2%
|
| -7 | Does not apply | 35 |
1.2%
|
| 0 | No obstacle | 1616 |
54.7%
|
| 1 | Minor obstacle | 512 |
17.3%
|
| 2 | Moderate obstacle | 473 |
16%
|
| 3 | Major obstacle | 223 |
7.5%
|
| 4 | Very severe obstacle | 60 |
2%
|