| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
1%
|
| 0 | No obstacle | 104 |
17.4%
|
| 1 | Minor obstacle | 133 |
22.2%
|
| 2 | Moderate obstacle | 110 |
18.4%
|
| 3 | Major obstacle | 151 |
25.3%
|
| 4 | Very severe obstacle | 94 |
15.7%
|