| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 1 |
0.2%
|
| 0 | No obstacle | 179 |
29.7%
|
| 1 | Minor obstacle | 177 |
29.4%
|
| 2 | Moderate obstacle | 103 |
17.1%
|
| 3 | Major obstacle | 92 |
15.3%
|
| 4 | Very severe obstacle | 50 |
8.3%
|