Unless all the names on the master list are to be placed in the jury wheel pursuant to Section 13-5-10, the names or identifying numbers of prospective jurors to be placed in the jury wheel shall be selected by the jury commission at random from the master list in the following manner: The total number of names on the master list shall be divided by the number of names to be placed in the jury wheel; the whole number nearest the quotient shall be the “key number,” except that the key number shall never be less than two (2). A “starting number” for making the selection shall then be determined by a random method from the number from one (1) to the key number, both inclusive. The required number of names shall then be selected from the master list by taking in order the first name on the master list corresponding to the starting number and then successively the names appearing in the master list at intervals equal to the key number, recommencing if necessary at the start of the list until the required number of names has been selected. The name of any person who is under the age of twenty-one (21) years and the name of any person who has been permanently excused from jury service pursuant to Section 13-5-23(4) shall be passed over without interrupting the sequence of selection. Any person who has been excluded from the master list for jury service may be reinstated to the master list after one (1) year by requesting that the circuit clerk reinstate him to the master list. Upon recommencing at the start of the list, names previously selected from the master list shall be disregarded in selecting the additional names. The jury commission may use an electronic or mechanical system or device in carrying out its duties.