| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 13 |
0.9%
|
| -7 | Does not apply | 33 |
2.3%
|
| 0 | No obstacle | 1066 |
75.3%
|
| 1 | Minor obstacle | 128 |
9%
|
| 2 | Moderate obstacle | 75 |
5.3%
|
| 3 | Major obstacle | 66 |
4.7%
|
| 4 | Very severe obstacle | 35 |
2.5%
|