1937–1950: Aggregate covered earnings
1951–1977: Quarterly earnings data reported by employer
1978 to date: Annual wage, salary, and tip income (covered and noncovered) reported on Form W-2; covered self-employment income reported on Form 1040 SE a
1990 to date: Summary deferred compensation
1991 to date b: Taxable Medicare earnings above the taxable maximum
2004 to date: Detailed deferred compensation