| Value | Category |
|---|---|
| -999 | No response |
| -888 | Do not know |
| -666 | Cannot remember |
| 1 | Within 1st month |
| 2 | Within 2nd month |
| 3 | Within 3rd month |
| 4 | Within 4th month |
| 5 | Within 5th month |
| 6 | Within 6th month |
| 7 | Within 7th month |
| 8 | Within 8th month |
| 9 | Within 9th month |
| 10 | Within 10th month and beyond |
| Sysmiss |