| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
0.3%
|
| -7 | Does not apply | 84 |
5.5%
|
| 0 | No obstacle | 907 |
59.7%
|
| 1 | Minor obstacle | 119 |
7.8%
|
| 2 | Moderate obstacle | 366 |
24.1%
|
| 3 | Major obstacle | 32 |
2.1%
|
| 4 | Very severe obstacle | 5 |
0.3%
|