| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 303 |
60.4%
|
| 1 | Minor obstacle | 105 |
20.9%
|
| 2 | Moderate obstacle | 69 |
13.7%
|
| 3 | Major obstacle | 19 |
3.8%
|
| 4 | Very severe obstacle | 5 |
1%
|