| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 19 |
1.4%
|
| -7 | Does not apply | 138 |
10.4%
|
| 0 | No obstacle | 485 |
36.7%
|
| 1 | Minor obstacle | 322 |
24.3%
|
| 2 | Moderate obstacle | 247 |
18.7%
|
| 3 | Major obstacle | 74 |
5.6%
|
| 4 | Very severe obstacle | 38 |
2.9%
|