| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 23 |
1.9%
|
| -7 | Does not apply | 11 |
0.9%
|
| 0 | No obstacle | 970 |
78.3%
|
| 1 | Minor obstacle | 101 |
8.2%
|
| 2 | Moderate obstacle | 83 |
6.7%
|
| 3 | Major obstacle | 29 |
2.3%
|
| 4 | Very severe obstacle | 22 |
1.8%
|