| Value | Category | Cases | |
|---|---|---|---|
| 1 | Past week | 2 |
3.4%
|
| 2 | Past month | 5 |
8.5%
|
| 3 | More than a month | 18 |
30.5%
|
| 4 | Earlier than 2015 | 34 |
57.6%
|
| Sysmiss | 344 |