| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.9%
|
| -7 | Does not apply | 28 |
8.4%
|
| 0 | No obstacle | 196 |
59%
|
| 1 | Minor obstacle | 45 |
13.6%
|
| 2 | Moderate obstacle | 35 |
10.5%
|
| 3 | Major obstacle | 20 |
6%
|
| 4 | Very severe obstacle | 5 |
1.5%
|