If, within sixty days following adoption of the Zoning Ordinance by Council, a petition is filed with the City Recorder asking for submission of the Zoning Ordinance to the qualified voters of the City, such ordinance shall not take effect until the ordinance has been approved by a majority of the legal votes cast at any regular primary or general or special election called for that purpose. The petition must be signed by a number of qualified voters, in their own handwriting, residing in the area affected by the proposed zoning equal to not less then fifteen percent (15%) of the total legal votes cast in the affected area for all candidates for governor at the last preceding general election at which a governor was elected. Only qualified voters residing in the area affected by the proposed ordinance shall be eligible to vote with respect thereto. (Passed 3-20-79.)