| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.3%
|
| -7 | Does not apply | 9 |
0.9%
|
| 0 | No obstacle | 343 |
33.9%
|
| 1 | Minor obstacle | 262 |
25.9%
|
| 2 | Moderate obstacle | 233 |
23%
|
| 3 | Major obstacle | 139 |
13.7%
|
| 4 | Very severe obstacle | 24 |
2.4%
|