| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 |
0.7%
|
| -7 | Does not apply | 13 |
1.4%
|
| 0 | No obstacle | 453 |
47.4%
|
| 1 | Minor obstacle | 166 |
17.4%
|
| 2 | Moderate obstacle | 152 |
15.9%
|
| 3 | Major obstacle | 117 |
12.3%
|
| 4 | Very severe obstacle | 47 |
4.9%
|