| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 4 |
0.4%
|
| 0 | No obstacle | 186 |
20.2%
|
| 1 | Minor obstacle | 208 |
22.6%
|
| 2 | Moderate obstacle | 166 |
18.1%
|
| 3 | Major obstacle | 185 |
20.1%
|
| 4 | Very severe obstacle | 170 |
18.5%
|