| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 241 |
40.1%
|
| 1 | Minor obstacle | 116 |
19.3%
|
| 2 | Moderate obstacle | 99 |
16.5%
|
| 3 | Major obstacle | 114 |
19%
|
| 4 | Very severe obstacle | 29 |
4.8%
|