| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.2%
|
| -7 | Does not apply | 24 |
1.7%
|
| 0 | No obstacle | 1029 |
72.7%
|
| 1 | Minor obstacle | 147 |
10.4%
|
| 2 | Moderate obstacle | 110 |
7.8%
|
| 3 | Major obstacle | 62 |
4.4%
|
| 4 | Very severe obstacle | 41 |
2.9%
|