| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.6%
|
| -7 | Does not apply | 32 |
2.9%
|
| 0 | No obstacle | 703 |
64.7%
|
| 1 | Minor obstacle | 107 |
9.9%
|
| 2 | Moderate obstacle | 95 |
8.7%
|
| 3 | Major obstacle | 97 |
8.9%
|
| 4 | Very severe obstacle | 46 |
4.2%
|