| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.4%
|
| -7 | Does not apply | 16 |
2.2%
|
| 0 | No obstacle | 162 |
22.4%
|
| 1 | Minor obstacle | 69 |
9.5%
|
| 2 | Moderate obstacle | 171 |
23.7%
|
| 3 | Major obstacle | 134 |
18.5%
|
| 4 | Very severe obstacle | 168 |
23.2%
|