| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 15 |
1.5%
|
| -7 | Does not apply | 7 |
0.7%
|
| 0 | No obstacle | 639 |
63.4%
|
| 1 | Minor obstacle | 241 |
23.9%
|
| 2 | Moderate obstacle | 60 |
6%
|
| 3 | Major obstacle | 35 |
3.5%
|
| 4 | Very severe obstacle | 11 |
1.1%
|