| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.4%
|
| -7 | Does not apply | 2 |
0.3%
|
| 0 | No obstacle | 390 |
53.5%
|
| 1 | Minor obstacle | 136 |
18.7%
|
| 2 | Moderate obstacle | 77 |
10.6%
|
| 3 | Major obstacle | 58 |
8%
|
| 4 | Very severe obstacle | 63 |
8.6%
|