| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 13 |
1.3%
|
| -7 | Does not apply | 7 |
0.7%
|
| 0 | No obstacle | 677 |
65.9%
|
| 1 | Minor obstacle | 186 |
18.1%
|
| 2 | Moderate obstacle | 116 |
11.3%
|
| 3 | Major obstacle | 28 |
2.7%
|
| 4 | Very severe obstacle | 1 |
0.1%
|