| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 30 |
2.2%
|
| -7 | Does not apply | 15 |
1.1%
|
| 0 | No obstacle | 384 |
28.7%
|
| 1 | Minor obstacle | 244 |
18.2%
|
| 2 | Moderate obstacle | 287 |
21.5%
|
| 3 | Major obstacle | 235 |
17.6%
|
| 4 | Very severe obstacle | 142 |
10.6%
|