| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
1.2%
|
| -7 | Does not apply | 132 |
13.1%
|
| 0 | No obstacle | 562 |
55.8%
|
| 1 | Minor obstacle | 225 |
22.3%
|
| 2 | Moderate obstacle | 58 |
5.8%
|
| 3 | Major obstacle | 16 |
1.6%
|
| 4 | Very severe obstacle | 3 |
0.3%
|