District courts are established, within districts, in accordance with the following schedule:
(1) On the first Monday in December, 1966, the first, the twelfth, the fourteenth, the sixteenth, the twenty-fifth, and the thirtieth districts;
(2) On the first Monday in December, 1968, the second, the third, the fourth, the fifth, the sixth, the seventh, the eighth, the ninth, the tenth, the eleventh, the thirteenth, the fifteenth, the eighteenth, the twentieth, the twenty-first, the twenty-fourth, the twenty-sixth, the twenty-seventh, and the twenty-ninth districts;
(3) On the first Monday in December, 1970, the seventeenth, the nineteenth, the twenty-second, the twenty-third, and the twenty-eighth districts.