| Value | Category |
|---|---|
| 1 | 1 week or less |
| 2 | More than 1 week – less than 2 weeks |
| 3 | More than 2 weeks – less than 1 month |
| 4 | 1 month - less than 6 months |
| 5 | 6 months - less than 1 year |
| 6 | 1 year - less than 2 years |
| 7 | 2 years - less than 3 years |
| 8 | 3 years or more |
| 9 | Don't know |