| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.3%
|
| -7 | Does not apply | 1 |
0.3%
|
| 0 | No obstacle | 202 |
56%
|
| 1 | Minor obstacle | 108 |
29.9%
|
| 2 | Moderate obstacle | 37 |
10.2%
|
| 3 | Major obstacle | 7 |
1.9%
|
| 4 | Very severe obstacle | 5 |
1.4%
|