| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
1%
|
| -7 | Does not apply | 19 |
3.1%
|
| 0 | No obstacle | 150 |
24.5%
|
| 1 | Minor obstacle | 101 |
16.5%
|
| 2 | Moderate obstacle | 108 |
17.6%
|
| 3 | Major obstacle | 143 |
23.4%
|
| 4 | Very severe obstacle | 85 |
13.9%
|