| Variable | Year | Supplement |
|---|---|---|
| GUARD | 2003 | Person (core questionnaire) |
| GUARD | 2002 | Person (core questionnaire) |
| GUARD | 2001 | Person (core questionnaire) |
| GUARD | 2000 | Person (core questionnaire) |
| GUARD | 1999 | Person (core questionnaire) |
| GUARD | 1998 | Person (core questionnaire) |