| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.3%
|
| -7 | Does not apply | 68 |
3.1%
|
| 0 | No obstacle | 1874 |
85.6%
|
| 1 | Minor obstacle | 149 |
6.8%
|
| 2 | Moderate obstacle | 58 |
2.6%
|
| 3 | Major obstacle | 26 |
1.2%
|
| 4 | Very severe obstacle | 8 |
0.4%
|