| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 6 |
1.2%
|
| 0 | No obstacle | 140 |
27.4%
|
| 1 | Minor obstacle | 208 |
40.7%
|
| 2 | Moderate obstacle | 99 |
19.4%
|
| 3 | Major obstacle | 55 |
10.8%
|
| 4 | Very severe obstacle | 3 |
0.6%
|