| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 12 |
4.8%
|
| 1 | Airport | 24 |
9.6%
|
| 2 | Land border crossing | 18 |
7.2%
|
| 3 | Seaport or waterway | 197 |
78.5%
|
| Sysmiss | 1938 |