Variable | Year | Supplement |
---|---|---|
HEARLEAR | 1991 | Hearing |
HEARLEAR | 1990 | Hearing |
HEARLEAR | 1977 | Hearing |
HEARLFT | 1999 | Sample adult questionnaire |
HRLEFT | 2008 | Sample adult questionnaire |
HRLEFT | 2007 | Sample adult questionnaire |
PS_489 | 1971 | Hearing |