| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
2.6%
|
| 1 | Airport | 4 |
10.5%
|
| 2 | Land border crossing | 3 |
7.9%
|
| 3 | Seaport or waterway | 30 |
78.9%
|
| Sysmiss | 392 |