| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
1.1%
|
| -7 | Does not apply | 14 |
1.4%
|
| 0 | No obstacle | 549 |
53.4%
|
| 1 | Minor obstacle | 242 |
23.5%
|
| 2 | Moderate obstacle | 147 |
14.3%
|
| 3 | Major obstacle | 58 |
5.6%
|
| 4 | Very severe obstacle | 7 |
0.7%
|