Mich. Comp. Laws § 331.102

Sec. 2. The tax provided for herein shall be apportioned and collected as other taxes for county purposes. Said tax shall not exceed 2/10 of 1 mill on each dollar of assessed valuation of said county, unless the same shall have been submitted to a vote of the qualified electors of such county: Provided, That in counties having a population of 25,000 or more it shall be lawful to assess and levy a tax of not to exceed 1 mill on each dollar of assessed valuation of said county for a period of not exceeding 2 years for the purpose of constructing or assisting to construct a hospital or sanitarium within said county.