| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.2%
|
| -7 | Does not apply | 21 |
2.1%
|
| 0 | No obstacle | 185 |
18.2%
|
| 1 | Minor obstacle | 153 |
15%
|
| 2 | Moderate obstacle | 182 |
17.9%
|
| 3 | Major obstacle | 275 |
27%
|
| 4 | Very severe obstacle | 201 |
19.7%
|