| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 |
1.1%
|
| 1 | Airport | 73 |
21%
|
| 2 | Land border crossing | 52 |
14.9%
|
| 3 | Seaport or waterway | 219 |
62.9%
|
| Sysmiss | 2349 |