| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 16 |
0.6%
|
| -7 | Does not apply | 15 |
0.6%
|
| 0 | No obstacle | 2284 |
84.7%
|
| 1 | Minor obstacle | 279 |
10.3%
|
| 2 | Moderate obstacle | 74 |
2.7%
|
| 3 | Major obstacle | 20 |
0.7%
|
| 4 | Very severe obstacle | 9 |
0.3%
|