| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.7%
|
| -7 | Does not apply | 128 |
20.9%
|
| 0 | No obstacle | 226 |
36.9%
|
| 1 | Minor obstacle | 154 |
25.2%
|
| 2 | Moderate obstacle | 66 |
10.8%
|
| 3 | Major obstacle | 25 |
4.1%
|
| 4 | Very severe obstacle | 9 |
1.5%
|