| 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 | June 2020 |
| 10 | July 2020 |
| 11 | August 2020 |
| 12 | Don't know |
| 13 | Refused to answer |
| 14 | Outlier set to missing |
| 15 | Inconsistency set to missing |
| 16 | Not applicable |