| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.5%
|
| -7 | Does not apply | 19 |
5%
|
| 0 | No obstacle | 18 |
4.7%
|
| 1 | Minor obstacle | 67 |
17.6%
|
| 2 | Moderate obstacle | 84 |
22.1%
|
| 3 | Major obstacle | 138 |
36.3%
|
| 4 | Very severe obstacle | 52 |
13.7%
|