| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.8%
|
| -7 | Does not apply | 25 |
6.6%
|
| 0 | No obstacle | 124 |
32.9%
|
| 1 | Minor obstacle | 27 |
7.2%
|
| 2 | Moderate obstacle | 66 |
17.5%
|
| 3 | Major obstacle | 56 |
14.9%
|
| 4 | Very severe obstacle | 76 |
20.2%
|