| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 174 |
28%
|
| 1 | Minor obstacle | 215 |
34.6%
|
| 2 | Moderate obstacle | 113 |
18.2%
|
| 3 | Major obstacle | 90 |
14.5%
|
| 4 | Very severe obstacle | 29 |
4.7%
|