| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
1.8%
|
| 1 | Airport | 22 |
13.5%
|
| 2 | Land border crossing | 0 |
0%
|
| 3 | Seaport or waterway | 138 |
84.7%
|
| Sysmiss | 198 |