| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.4%
|
| -7 | Does not apply | 13 |
1.3%
|
| 0 | No obstacle | 113 |
11.1%
|
| 1 | Minor obstacle | 84 |
8.2%
|
| 2 | Moderate obstacle | 179 |
17.6%
|
| 3 | Major obstacle | 241 |
23.7%
|
| 4 | Very severe obstacle | 385 |
37.8%
|