| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 20 |
1.2%
|
| -7 | Does not apply | 87 |
5%
|
| 0 | No obstacle | 724 |
42%
|
| 1 | Minor obstacle | 361 |
20.9%
|
| 2 | Moderate obstacle | 288 |
16.7%
|
| 3 | Major obstacle | 160 |
9.3%
|
| 4 | Very severe obstacle | 85 |
4.9%
|