(1) All petitions that are presented to the election commissioner or county clerk for signature verification shall be retained in the election office and shall be open to public inspection. Upon receipt of the pages of a petition, the election commissioner or county clerk shall issue a written receipt indicating the number of pages of the petition in his or her custody to the person presenting the petition for signature verification. Petitions may be destroyed twenty-two months after the election to which they apply.
(2) The election commissioner or county clerk shall determine the validity and sufficiency of such petition by comparing the names, dates of birth if applicable, and addresses of the signers with the voter registration records to determine if the signers were registered voters on the date of signing the petition. If it is determined that a signer has affixed his or her signature more than once to any petition and that only one person is registered by that name, the election commissioner or county clerk shall strike from the pages of the petition all but one such signature. Only one of the duplicate signatures shall be added to the total number of valid signatures. All signatures, dates of birth, and addresses shall be presumed to be valid if the election commissioner or county clerk has found the signers to be registered voters on or before the date on which the petition was signed. This presumption shall not be conclusive and may be rebutted by any credible evidence which the election commissioner or county clerk finds sufficient.
(3) If the election commissioner or county clerk verifies signatures in excess of one hundred ten percent of the number necessary for the issue to be placed on the ballot, the election commissioner or county clerk may cease verifying signatures and certify the number of signatures verified to the person who delivered the petitions for verification.
(4) If the number of signatures verified does not equal or exceed the number necessary to place the issue on the ballot upon completion of the comparison of names and addresses with the voter registration records, the election commissioner or county clerk shall prepare in writing a certification under seal setting forth the name and address of each signer found not to be a registered voter and the petition page number and line number where the signature is found. If the signature or address is challenged for a reason other than the nonregistration of the signer, the election commissioner or county clerk shall set forth the reasons for the challenge of the signature.