The voters shall have power to propose any ordinances, except an appropriation ordinance or an ordinance making a tax levy, and to adopt or reject the same at any polls, such power being known as the initiative. Any initiated ordinance may be submitted to the commission by petition signed by voters of the city equal in number to at least ten percent of those who voted at the last regular municipal election, provided, however, that the petition must bear the signatures of at least one hundred voters of the city. All petition papers circulated with respect to an initiated resolution or ordinance shall be uniform in character and shall contain the proposed resolution or ordinance in full.