| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 16 |
0.7%
|
| -7 | Does not apply | 102 |
4.7%
|
| 0 | No obstacle | 2008 |
91.7%
|
| 1 | Minor obstacle | 41 |
1.9%
|
| 2 | Moderate obstacle | 10 |
0.5%
|
| 3 | Major obstacle | 6 |
0.3%
|
| 4 | Very severe obstacle | 6 |
0.3%
|