| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.6%
|
| -7 | Does not apply | 37 |
10.2%
|
| 0 | No obstacle | 175 |
48.5%
|
| 1 | Minor obstacle | 59 |
16.3%
|
| 2 | Moderate obstacle | 53 |
14.7%
|
| 3 | Major obstacle | 23 |
6.4%
|
| 4 | Very severe obstacle | 12 |
3.3%
|