(1) The jury commissioner, at such times as may be necessary or as he or she may be ordered to do so by the district judge, shall draw a number to be known as a key number. The drawing of a key number shall be done in a manner which will ensure that the number drawn is the result of chance. The key number shall be drawn from among the numbers one to ten. Except as otherwise provided in this section, only one key number need be drawn.
(2) In a county with a population of less than three thousand inhabitants, the jury commissioner shall draw two key numbers or such larger number of key numbers as the district judge or judges may order instead of only one.
(3) In a county with a population of three thousand inhabitants or more, where experience demonstrates that the use of only one key number does not produce a list of names of sufficient number to make the system of practical use, the district judge or judges may, in their discretion, order the selecting of two key numbers.
(4) The jury commissioner shall make a record of the manner in which the key number or numbers were drawn and the date and the hour of the drawing, the same to be certified by the jury commissioner, and such records shall be entered upon the record of the court.