| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 16 |
1.1%
|
| -7 | Does not apply | 80 |
5.5%
|
| 0 | No obstacle | 811 |
56.1%
|
| 1 | Minor obstacle | 219 |
15.1%
|
| 2 | Moderate obstacle | 169 |
11.7%
|
| 3 | Major obstacle | 85 |
5.9%
|
| 4 | Very severe obstacle | 66 |
4.6%
|