Beneficiaries affected by the annual earnings test in 1978.
D000367:Age Factors; D000368:Aged; D004608:Eligibility Determination; D005260:Female; D006801:Humans; D007182:Income; D007341:Insurance; D008297:Male; D008875:Middle Aged; D012179:Retirement; D012737:Sex Factors; D012943:Social Security; D014481:United States