| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 13 |
1.7%
|
| -7 | Does not apply | 79 |
10.2%
|
| 0 | No obstacle | 451 |
58.4%
|
| 1 | Minor obstacle | 130 |
16.8%
|
| 2 | Moderate obstacle | 66 |
8.5%
|
| 3 | Major obstacle | 27 |
3.5%
|
| 4 | Very severe obstacle | 6 |
0.8%
|