| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 6 |
0.4%
|
| -7 | Does not apply (spontaneous) | 40 |
2.5%
|
| 0 | No obstacle | 1159 |
73.7%
|
| 1 | Minor obstacle | 194 |
12.3%
|
| 2 | Moderate obstacle | 102 |
6.5%
|
| 3 | Major obstacle | 50 |
3.2%
|
| 4 | Very severe obstacle | 22 |
1.4%
|