(a) All such wages have remained unpaid to such person, and

(b) No written communication has been received from such person by the holder, and

(c) Notice regarding such wages, if sent by the broker or dealer, via first class mail, to such person at his last known address has been returned to the broker or dealer by the postal authorities for inability to locate such person. 6. Any broker or dealer who satisfies the requirements of this subdivision may determine the property which on the thirty-first day of December in the years nineteen hundred seventy-two, nineteen hundred seventy-three, nineteen hundred seventy-four and nineteen hundred seventy-five shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the years nineteen hundred sixty-seven, nineteen hundred sixty-eight, nineteen hundred sixty-nine, and nineteen hundred seventy by the method hereinafter in this subdivision described and the amount so determined as at any such date shall be deemed to be all of such abandoned property held by such broker or dealer pursuant to subdivisions one and three of this section on such date. The broker or dealer shall compute separately for each of the years nineteen hundred sixty-five and nineteen hundred sixty-six (each of which years is referred to in this subdivision as a "base year") the total value of all stock and cash dividends received by such broker or dealer, or nominee of such broker or dealer, in this state during such year as the holder of record of a security. The value of any dividend paid in stock shall be the mean price of such stock during the calendar month in which the dividend was received as reported by any generally recognized statistical service or, if not so reported, as established in any other manner satisfactory to the state comptroller. The total value of all such stock and cash dividends thus determined for each base year shall be the denominator for that base year. The broker or dealer shall then determine the total value of all such dividends received during each base year belonging to unknown owners as reported to the state comptroller, or as required to be so reported pursuant to this article, which continued to be held by such broker or dealer, or nominee of such broker or dealer, unpaid to the person entitled thereto on the December thirty-first occurring five years after the close of such base year. To the extent any such dividends which continued to be so held unpaid on any such December thirty-first consisted of stock, such stock shall be valued at the mean price of such stock during the calendar month ending on such December thirty-first as reported by any generally recognized statistical service or, if not so reported, as established in any other manner satisfactory to the state comptroller. The total value of such remaining dividends thus determined for each base year shall be the numerator for that base year. The sum of the numerators for the base years shall be divided by the sum of the denominators for the base years and the result thus obtained shall be multiplied by two. The product obtained as the result of such multiplication shall be the average factor of such broker or dealer. In order to determine the property which on the thirty-first day of December, nineteen hundred seventy-two shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-seven the broker or dealer shall determine (i) the total value of all stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-seven as the holder of record of a security and shall multiply such total value by the average factor of such broker or dealer, (ii) the aggregate amount of stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-seven as the holder of record of a security for a person or persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-two in covering stock and cash dividends which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-seven but, according to the books and records of such broker or dealer, were not received, and (iii) the aggregate amount of interest payments received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-seven on securities held for persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-two in covering interest payments which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-seven but, according to the books and records of such broker or dealer, were not received. The greater of the two amounts determined pursuant to clauses (i) and (ii) of the preceding sentence, plus the amount determined pursuant to clause (iii) of such sentence, shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-seven on the thirty-first day of December nineteen hundred seventy-two. In order to determine the property which on the thirty-first day of December, nineteen hundred seventy-three shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-eight the broker or dealer shall determine (i) the total value of all stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-eight as the holder of record of a security and shall multiply such total value by the average factor of such broker or dealer, (ii) the aggregate amount of stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-eight as the holder of record of a security for a person or persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-three in covering stock and cash dividends which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-eight but, according to the books and records of such broker or dealer, were not received, and (iii) the aggregate amount of interest payments received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-eight on securities held for persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-three in covering interest payments which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-eight but, according to the books and records of such broker or dealer, were not received. The greater of the two amounts determined pursuant to clauses (i) and (ii) of the preceding sentence, plus the amount determined pursuant to clause (iii) of such sentence, shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-eight on the thirty-first day of December, nineteen hundred seventy-three. In order to determine the property which on the thirty-first day of December, nineteen hundred seventy-four shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-nine the broker or dealer shall determine (i) the total value of all stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-nine as the holder of record of a security and shall multiply such total value by the average factor of such broker or dealer, (ii) the aggregate amount of stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-nine as the holder of record of a security for a person or persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-four in covering stock and cash dividends which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-nine but, according to the books and records of such broker or dealer, were not received, and (iii) the aggregate amount of interest payments received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-nine on securities held for persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-four in covering interest payments which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred sixty-nine but, according to the books and records of such broker or dealer, were not received. The greater of the two amounts determined pursuant to clauses (i) and (ii) of the preceding sentence, plus the amount determined pursuant to clause (iii) of such sentence, shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-nine on the thirty-first day of December nineteen hundred seventy-four. In order to determine the property which on the thirty-first day of December, nineteen hundred seventy-five shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred seventy the broker or dealer shall determine (i) the total value of all stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred seventy as the holder of record of a security and shall multiply such total value by the average factor of such broker or dealer, (ii) the aggregate amount of stock and cash dividends (valued as above provided) received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred seventy as the holder of record of a security for a person or persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-five in covering stock and cash divi- dends which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred seventy but, according to the books and records of such broker or dealer, were not received, and (iii) the aggregate amount of interest payments received by such broker or dealer, or nominee of such broker or dealer, in this state during nineteen hundred sixty-nine on securities held for persons unknown to such broker or dealer, less the cost incurred by such broker or dealer not later than the thirty-first day of December, nineteen hundred seventy-five in covering interest payments which should have been received by such broker or dealer, or nominee of such broker or dealer, during nineteen hundred seventy but, according to the books and records of such broker or dealer, were not received. The greater of the two amounts determined pursuant to clauses (i) and (ii) of the preceding sentence, plus the amount determined pursuant to clause (iii) of such sentence, shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred seventy on the thirty-first day of December, nineteen hundred seventy-five. Each broker or dealer which uses the procedure described above in this subdivision shall maintain for a period of not less than six years commencing January first, nineteen hundred seventy-two, books and records evidencing the receipt of dividends in this state for each of the base years, and the payment thereof over the five years succeeding each base year. Any broker or dealer who chooses to determine the property which on the thirty-first day of December in the years nineteen hundred seventy-two or nineteen hundred seventy-three shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the years nineteen hundred sixty-seven or nineteen hundred sixty-eight by the method described in this subdivision shall thereafter determine the property which on the thirty-first day of December in each subsequent year ending not later than December thirty-first, nineteen hundred seventy-five shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to a year not later than nineteen hundred seventy by the method described in this subdivision. No broker or dealer may choose to determine the property which on the thirty-first day of December in the years nineteen hundred seventy-four or nineteen hundred seventy-five shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the years nineteen hundred sixty-nine or nineteen hundred seventy by the method described in this subdivision unless such broker or dealer shall have used the method described in this subdivision to determine the property which on the thirty-first day of December in the year nineteen hundred seventy-three shall be deemed abandoned property pursuant to subdivisions one and three of this section relating to the year nineteen hundred sixty-eight. The method of determining abandoned property pursuant to subdivisions one and three of this section as described in this subdivision shall be available only to such brokers or dealers as have made written reports pursuant to section five hundred thirteen in each of the years nineteen hundred seventy-one and nineteen hundred seventy-two covering each of the base years. In the event that an audit of a broker or dealer by the state comptroller establishes that one or more of the dollar values determined by the broker or dealer for the purpose of computing the average factor of such broker or dealer pursuant to this subdivision was incorrect, the corrected average factor of such broker or dealer established as a result of such audit shall be determined to be the average factor required to be used by such broker or dealer in determining abandoned property pursuant to this subdivision. Any broker or dealer who does not determine abandoned property pursuant to subdivisions one and three of this section by the method described in this subdivision and who during any of the calendar years nineteen hundred sixty-seven, nineteen hundred sixty-eight, nineteen hundred sixty-nine or nineteen hundred seventy received in this state any stock dividend as the holder of record of a security for a person or persons unknown to such broker or dealer and who sold any such stock dividend during any such or subsequent calendar year, shall pay the proceeds of such sale to the state comptroller not later than the thirty-first day of December, nineteen hundred seventy-three and such proceeds shall, for all purposes of this chapter be deemed abandoned property on the thirty-first day of December of the calendar year during which such sale takes place.