| Value | Category |
|---|---|
| 1 | Yesterday/today |
| 2 | In the past 7 days |
| 3 | In the past 30 days |
| 4 | In the past 60 days |
| 5 | More than 60 days but less than 90 days ago |
| 6 | More than 90 but less than 6 months ago |
| 7 | More than 6 months ago but within the past 12 months |
| 8 | More than 12 months ago |
| Sysmiss |