| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.9%
|
| -7 | Does not apply | 73 |
11.3%
|
| 0 | No obstacle | 105 |
16.3%
|
| 1 | Minor obstacle | 92 |
14.3%
|
| 2 | Moderate obstacle | 147 |
22.8%
|
| 3 | Major obstacle | 149 |
23.1%
|
| 4 | Very severe obstacle | 73 |
11.3%
|