In determining whether this chapter shall become operative, the director shall find that at least 40 percent of the total number of vintners from the list established by the director participated in the referendum, and that either one of the following has occurred:
(a)
Sixty-five percent or more of the vintners who voted in the referendum voted in favor of this chapter, and the vintners so voting processed a majority of the volume of winegrapes in the preceding marketing season by all the vintners who voted in the referendum.
(b)
A majority of the vintners who voted in the referendum voted in favor of this chapter, and the vintners so voting processed 65 percent or more of the volume of winegrapes in the preceding marketing season by all the vintners who voted in the referendum.