| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
0.9%
|
| -7 | Does not apply | 258 |
12.9%
|
| 0 | No obstacle | 1440 |
72.2%
|
| 1 | Minor obstacle | 101 |
5.1%
|
| 2 | Moderate obstacle | 94 |
4.7%
|
| 3 | Major obstacle | 55 |
2.8%
|
| 4 | Very severe obstacle | 29 |
1.5%
|