Within 30 days after the receipt of the petition, the county elections official shall examine the petition and determine the number of valid signers thereof by comparing the signatures thereon with the signatures of registered voters as appear on the affidavits of voter registration on file with him or her. The county elections official then shall certify to the secretary of the district all the following:
(a) The total number of voters registered within the district at the time of the last general statewide election immediately preceding the filing of the petition.
(b) The total number of registered voters of the district who have signed the petition.
(c) The percentage which the number of such signers bears to the total number of voters registered to vote within the district at such time.