An initiatory or a referendary petition shall be signed by not less than fifteen percent of the registered electors of the City who have signed said petition within ninety days before the date of filing the petition with the Clerk. No such petition need be on one paper, but may be aggregate of two or more petition papers. Each signer of a petition shall sign his name in ink or indelible pencil, and shall place thereon, after his name, the date and his place of residence by street and number. To each petition paper there shall be attached a sworn affidavit by the circulator thereof, stating the number of signers thereto and that each signature thereon is the genuine signature of the person whose name it purports to be, and that it was made in the presence of the affiant. Such petition shall be filed with the Clerk who shall, within ten days, canvass the signatures thereon to determine the sufficiency thereof. Any signatures obtained more than ninety days before the filing of such petition with the Clerk shall not be counted. E found to contain an insufficient number of signatures of registered electors of the City, or to be improper as to form or compliance with the provisions of this section, the Clerk shall notify forthwith the person filing such petition, and ten days from such notification shall be allowed for the filing of supplemental petition papers. When found sufficient and proper, the Clerk shall present the petition to the Council at its next regular meeting.