| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 15 |
4.2%
|
| 0 | No obstacle | 281 |
78.5%
|
| 1 | Minor obstacle | 36 |
10.1%
|
| 2 | Moderate obstacle | 15 |
4.2%
|
| 3 | Major obstacle | 7 |
2%
|
| 4 | Very severe obstacle | 3 |
0.8%
|