| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 28 |
0.2%
|
| -7 | Does not apply | 21 |
0.1%
|
| 0 | No obstacle | 7947 |
42.6%
|
| 1 | Minor obstacle | 5651 |
30.3%
|
| 2 | Moderate obstacle | 2878 |
15.4%
|
| 3 | Major obstacle | 1674 |
9%
|
| 4 | Very severe obstacle | 458 |
2.5%
|