| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 150 |
25%
|
| 1 | Minor obstacle | 137 |
22.8%
|
| 2 | Moderate obstacle | 99 |
16.5%
|
| 3 | Major obstacle | 138 |
23%
|
| 4 | Very severe obstacle | 76 |
12.7%
|