| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.5%
|
| -7 | Does not apply | 37 |
6%
|
| 0 | No obstacle | 195 |
31.7%
|
| 1 | Minor obstacle | 112 |
18.2%
|
| 2 | Moderate obstacle | 106 |
17.2%
|
| 3 | Major obstacle | 110 |
17.9%
|
| 4 | Very severe obstacle | 52 |
8.5%
|