| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 3 |
0.8%
|
| 0 | No obstacle | 229 |
63.8%
|
| 1 | Minor obstacle | 74 |
20.6%
|
| 2 | Moderate obstacle | 31 |
8.6%
|
| 3 | Major obstacle | 15 |
4.2%
|
| 4 | Very severe obstacle | 6 |
1.7%
|