| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
0.7%
|
| -7 | Does not apply | 518 |
19.7%
|
| 0 | No obstacle | 877 |
33.3%
|
| 1 | Minor obstacle | 419 |
15.9%
|
| 2 | Moderate obstacle | 566 |
21.5%
|
| 3 | Major obstacle | 172 |
6.5%
|
| 4 | Very severe obstacle | 65 |
2.5%
|