in computing an individual’s average indexed monthly earnings or, in the case of an individual whose primary insurance amount is computed under subsection (a) as in effect prior to January 1979, average monthly wage, there shall not be counted the excess over $3,600 in the case of any calendar year after 1950 and before 1955, the excess over $4,200 in the case of any calendar year after 1954 and before 1959, the excess over $4,800 in the case of any calendar year after 1958 and before 1966, the excess over $6,600 in the case of any calendar year after 1965 and before 1968, the excess over $7,800 in the case of any calendar year after 1967 and before 1972, the excess over $9,000 in the case of any calendar year after 1971 and before 1973, the excess over $10,800 in the case of any calendar year after 1972 and before 1974, the excess over $13,200 in the case of any calendar year after 1973 and before 1975, and the excess over an amount equal to the contribution and benefit base (as determined under section 430 of this title ) in the case of any calendar year after 1974 with respect to which such contribution and benefit base is effective, (before the application, in the case of average indexed monthly earnings, of subsection (b)(3)(A)) of (A) the wages paid to him in such year, plus (B) the self-employment income credited to such year (as determined under section 412 of this title ); and