1. The membership composition of a regional planning commission shall be in accordance with resolutions approved by the governing bodies of the local units in the region, representing in the aggregate at least half of the population of the region. For the purposes of this determination, a county shall be as one local unit and the population of such county shall be based upon the inhabitants residing in the unincorporated area of such county as determined by the last decennial census of the United States.

2. Terms of office for regional planning commission members shall be as prescribed in the resolutions of approval; all regional planning commission members shall be electors of the state and reside within the region.