((a)) ** Definitions** For the purposes of this subchapter—

((1)) The term “quarter”, and the term “calendar quarter”, mean a period of three calendar months ending on March 31, June 30, September 30, or December 31.

((2))

((A)) The term “quarter of coverage” means—

((i)) for calendar years before 1978, and subject to the provisions of subparagraph (B), a quarter in which an individual has been paid $50 or more in wages (except wages for agricultural labor paid after 1954) or for which he has been credited (as determined under ) with $100 or more of self-employment income; and

((ii)) for calendar years after 1977, and subject to the provisions of subparagraph (B), each portion of the total of the wages paid and the self-employment income credited (pursuant to ) to an individual in a calendar year which equals the amount required for a quarter of coverage in that calendar year (as determined under subsection (d)), with such quarter of coverage being assigned to a specific calendar quarter in such calendar year only if necessary in the case of any individual who has attained age 62 or died or is under a disability and the requirements for insured status in subsection (a) or (b) of , the requirements for entitlement to a computation or recomputation of his primary insurance amount, or the requirements of paragraph (3) of would not otherwise be met.

((B)) Notwithstanding the provisions of subparagraph (A)—

((i)) no quarter after the quarter in which an individual dies shall be a quarter of coverage, and no quarter any part of which is included in a period of disability (other than the initial quarter and the last quarter of such period) shall be a quarter of coverage;

((ii)) if the wages paid to an individual in any calendar year equal $3,000 in the case of a calendar year before 1951, or $3,600 in the case of a calendar year after 1950 and before 1955, or $4,200 in the case of a calendar year after 1954 and before 1959, or $4,800 in the case of a calendar year after 1958 and before 1966, or $6,600 in the case of a calendar year after 1965 and before 1968, or $7,800 in the case of a calendar year after 1967 and before 1972, or $9,000 in the case of the calendar year 1972, or $10,800 in the case of the calendar year 1973, or $13,200 in the case of the calendar year 1974, or an amount equal to the contribution and benefit base (as determined under ) in the case of any calendar year after 1974 and before 1978 with respect to which such contribution and benefit base is effective, each quarter of such year shall (subject to clauses (i) and (v)) be a quarter of coverage;

((iii)) if an individual has self-employment income for a taxable year, and if the sum of such income and the wages paid to him during such year equals $3,600 in the case of a taxable year beginning after 1950 and ending before 1955, or $4,200 in the case of a taxable year ending after 1954 and before 1959, or $4,800 in the case of a taxable year ending after 1958 and before 1966, or $6,600 in the case of a taxable year ending after 1965 and before 1968, or $7,800 in the case of a taxable year ending after 1967 and before 1972, or $9,000 in the case of a taxable year beginning after 1971 and before 1973, or $10,800 in the case of a taxable year beginning after 1972 and before 1974, or $13,200 in the case of a taxable year beginning after 1973 and before 1975, or an amount equal to the contribution and benefit base (as determined under ) which is effective for the calendar year in the case of any taxable year beginning in any calendar year after 1974 and before 1978, each quarter any part of which falls in such year shall (subject to clauses (i) and (v)) be a quarter of coverage;

((iv)) if an individual is paid wages for agricultural labor in a calendar year after 1954 and before 1978, then, subject to clauses (i) and (v), (I) the last quarter of such year which can be but is not otherwise a quarter of coverage shall be a quarter of coverage if such wages equal or exceed $100 but are less than $200; (II) the last two quarters of such year which can be but are not otherwise quarters of coverage shall be quarters of coverage if such wages equal or exceed $200 but are less than $300; (III) the last three quarters of such year which can be but are not otherwise quarters of coverage shall be quarters of coverage if such wages equal or exceed $300 but are less than $400; and (IV) each quarter of such year which is not otherwise a quarter of coverage shall be a quarter of coverage if such wages are $400 or more;

((v)) no quarter shall be counted as a quarter of coverage prior to the beginning of such quarter;

((vi)) not more than one quarter of coverage may be credited to a calendar quarter; and

((vii)) no more than four quarters of coverage may be credited to any calendar year after 1977.

((b)) ** Crediting of wages paid in 1937** With respect to wages paid to an individual in the six-month periods commencing either , or ; (A) if wages of not less than $100 were paid in any such period, one-half of the total amount thereof shall be deemed to have been paid in each of the calendar quarters in such period; and (B) if wages of less than $100 were paid in any such period, the total amount thereof shall be deemed to have been paid in the latter quarter of such period, except that if in any such period, the individual attained age sixty-five, all of the wages paid in such period shall be deemed to have been paid before such age was attained.January 1, 19371937-01-01July 1, 19371937-07-01

((c)) ** Alternative method for determining quarters of coverage with respect to wages in period from 1937 to 1950** For purposes of sections 414(a) and 415(d) of this title, an individual shall be deemed to have one quarter of coverage for each $400 of his total wages prior to 1951 (as defined in ), except where such individual is not a fully insured individual on the basis of the number of quarters of coverage so derived plus the number of quarters of coverage derived from the wages and self-employment income credited to such individual for periods after 1950.section 415(d)(1)(C) of this title

((d)) ** Amount required for a quarter of coverage**

((1)) The amount of wages and self-employment income which an individual must have in order to be credited with a quarter of coverage in any year under subsection (a)(2)(A)(ii) shall be $250 in the calendar year 1978 and the amount determined under paragraph (2) of this subsection for years after 1978.

((2)) The Commissioner of Social Security shall, on or before November 1 of 1978 and of every year thereafter, determine and publish in the Federal Register the amount of wages and self-employment income which an individual must have in order to be credited with a quarter of coverage in the succeeding calendar year. The amount required for a quarter of coverage shall be the larger of—

((A)) the amount in effect in the calendar year in which the determination under this subsection is made, or

((B)) the product of the amount prescribed in paragraph (1) which is required for a quarter of coverage in 1978 and the ratio of the national average wage index (as defined in ) for the calendar year before the year in which the determination under this paragraph is made to the national average wage index (as so defined) for 1976,