| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 21 |
5.9%
|
| 0 | No obstacle | 261 |
72.9%
|
| 1 | Minor obstacle | 20 |
5.6%
|
| 2 | Moderate obstacle | 32 |
8.9%
|
| 3 | Major obstacle | 17 |
4.7%
|
| 4 | Very severe obstacle | 5 |
1.4%
|