| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.3%
|
| -7 | Does not apply | 12 |
1.2%
|
| 0 | No obstacle | 638 |
65.2%
|
| 1 | Minor obstacle | 199 |
20.3%
|
| 2 | Moderate obstacle | 104 |
10.6%
|
| 3 | Major obstacle | 18 |
1.8%
|
| 4 | Very severe obstacle | 5 |
0.5%
|