| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 20 |
1.5%
|
| -7 | Does not apply | 19 |
1.4%
|
| 0 | No obstacle | 314 |
22.9%
|
| 1 | Minor obstacle | 296 |
21.6%
|
| 2 | Moderate obstacle | 355 |
25.9%
|
| 3 | Major obstacle | 239 |
17.5%
|
| 4 | Very severe obstacle | 126 |
9.2%
|