| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 |
1%
|
| -7 | Does not apply | 12 |
1.2%
|
| 0 | No obstacle | 137 |
13.4%
|
| 1 | Minor obstacle | 94 |
9.2%
|
| 2 | Moderate obstacle | 183 |
18%
|
| 3 | Major obstacle | 309 |
30.3%
|
| 4 | Very severe obstacle | 274 |
26.9%
|