| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
0.7%
|
| -7 | Does not apply | 49 |
8.2%
|
| 0 | No obstacle | 127 |
21.2%
|
| 1 | Minor obstacle | 89 |
14.9%
|
| 2 | Moderate obstacle | 105 |
17.6%
|
| 3 | Major obstacle | 140 |
23.4%
|
| 4 | Very severe obstacle | 84 |
14%
|