2-1-15. Examination of petition by secretary of state--Signatures not to be counted unless persons are registered voters and information is complete. Upon the receiving of any initiative petition, referred law petition, or initiated constitutional amendment petition, the secretary of state shall examine the petition. No signature of a person may be counted by the secretary of state unless the person is a registered voter in the county indicated on the signature line. No signature of a person may be counted if the information required on the petition form is not complete.