| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 30 |
2.4%
|
| -7 | Does not apply | 18 |
1.5%
|
| 0 | No obstacle | 1020 |
82.3%
|
| 1 | Minor obstacle | 81 |
6.5%
|
| 2 | Moderate obstacle | 47 |
3.8%
|
| 3 | Major obstacle | 24 |
1.9%
|
| 4 | Very severe obstacle | 19 |
1.5%
|