| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 |
1.3%
|
| -7 | Does not apply | 7 |
0.9%
|
| 0 | No obstacle | 473 |
61.3%
|
| 1 | Minor obstacle | 129 |
16.7%
|
| 2 | Moderate obstacle | 95 |
12.3%
|
| 3 | Major obstacle | 46 |
6%
|
| 4 | Very severe obstacle | 12 |
1.6%
|