| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 71 |
18.8%
|
| 1 | Minor obstacle | 52 |
13.8%
|
| 2 | Moderate obstacle | 92 |
24.3%
|
| 3 | Major obstacle | 73 |
19.3%
|
| 4 | Very severe obstacle | 85 |
22.5%
|