| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 |
7.6%
|
| 1 | Airport | 16 |
13.6%
|
| 2 | Land border crossing | 9 |
7.6%
|
| 3 | Seaport or waterway | 84 |
71.2%
|
| Sysmiss | 2071 |