| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 39 |
0.1%
|
| -7 | Does not apply | 33 |
0.1%
|
| 0 | No obstacle | 10008 |
34.3%
|
| 1 | Minor obstacle | 9224 |
31.7%
|
| 2 | Moderate obstacle | 6289 |
21.6%
|
| 3 | Major obstacle | 2593 |
8.9%
|
| 4 | Very severe obstacle | 950 |
3.3%
|