Self-employment income credited to calendar years

For the purposes of determining average monthly wage and quarters of coverage the amount of self-employment income derived during any taxable year which begins before 1978 shall— Except as provided in subsection (c), for the purposes of determining average indexed monthly earnings, average monthly wage, and quarters of coverage the amount of self-employment income derived during any taxable year which begins after 1977 shall— For the purpose of determining average indexed monthly earnings, average monthly wage, and quarters of coverage in the case of any individual who elects the option described in clause (ii) or (iv) in the matter following section 411(a)(16) of this title for any taxable year that does not begin with or during a particular calendar year and end with or during such year, the self-employment income of such individual deemed to be derived during such taxable year shall be allocated to the two calendar years, portions of which are included within such taxable year, in the same proportion to the total of such deemed self-employment income as the sum of the amounts applicable under section 413(d) of this title for the calendar quarters ending with or within each such calendar year bears to the lower limit for such taxable year specified in section 411(k)(1) of this title.