| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
1%
|
| 1 | Airport | 3 |
3%
|
| 2 | Land border crossing | 94 |
94%
|
| 3 | Seaport or waterway | 2 |
2%
|
| Sysmiss | 913 |