| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.4%
|
| 1 | Airport | 23 |
8.9%
|
| 2 | Land border crossing | 48 |
18.7%
|
| 3 | Seaport or waterway | 185 |
72%
|
| Sysmiss | 335 |