| Value | Category |
|---|---|
| 1 | In the past 7 days |
| 2 | In the 7 days before that (between 14 to 7 days ago) |
| 3 | May 2020 |
| 4 | April 2020 |
| 5 | March 2020 |
| 6 | February 2020 |
| 7 | January 2020 |
| 8 | Before January 2020 |
| 9 | 9 |
| 10 | 10 |
| 11 | 11 |
| 12 | 14 |
| 13 | 15 |
| 14 | 16 |
| 15 | Don't know |
| 16 | Refused to answer |
| 17 | Outlier set to missing |
| 18 | Inconsistency set to missing |
| 19 | Not applicable |