| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 22 |
1.6%
|
| -7 | Does not apply | 43 |
3.1%
|
| 0 | No obstacle | 620 |
45.3%
|
| 1 | Minor obstacle | 211 |
15.4%
|
| 2 | Moderate obstacle | 243 |
17.8%
|
| 3 | Major obstacle | 170 |
12.4%
|
| 4 | Very severe obstacle | 60 |
4.4%
|