| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.6%
|
| -7 | Does not apply | 16 |
1.3%
|
| 0 | No obstacle | 334 |
27.8%
|
| 1 | Minor obstacle | 229 |
19.1%
|
| 2 | Moderate obstacle | 222 |
18.5%
|
| 3 | Major obstacle | 216 |
18%
|
| 4 | Very severe obstacle | 176 |
14.7%
|