The county board of commissioners in all counties having not more than four hundred thousand inhabitants as determined by the most recent federal decennial census shall consist of three persons except as follows:

(1) Pursuant to petitions filed or a vote of the county board under section 23-149, the registered voters in any county containing not more than four hundred thousand inhabitants as determined by the most recent federal decennial census may vote at any general election as to whether their county board shall consist of three or five commissioners. Upon the completion of the canvass by the county canvassing board, the proposition shall be decided and, if the number of commissioners is increased from three to five commissioners, vacancies shall be deemed to exist and the procedures set forth in sections 32-567 and 32-574 shall be instituted; and

(2) The registered voters of any county under township organization voting to discontinue township organization may also vote as to the number of county commissioners as provided in sections 23-292 to 23-299.

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