Upon petition of ten percent of the number of qualified electors of the county voting in the last election for governor or upon its own motion, the board of county commissioners of each county shall levy annually a tax not exceeding the limitation in subsection 10 of section 57-15-06.7, for the purpose of subsidizing county emergency medical services; provided, that this tax must be approved by a majority of the qualified electors of the county voting on the question at a regular or special countywide election. The county may budget, in addition to its annual operating budget for subsidizing emergency medical service, no more than ten percent of its annual operating budget as a depreciation expense to be set aside in a dedicated emergency medical services sinking fund deposited with the treasurer for the replacement of equipment and ambulances. The ten percent emergency medical services sinking fund must be in addition to the annual operating budget for subsidization, but the total of the annual operating budget and the annual ten percent emergency medical services sinking fund may not exceed the approved mill levy. If the county contains a rural ambulance service district or rural fire protection district that levies for and provides emergency medical service, the property within that district is exempt from the county tax levy under this section upon notice from the governing body of the district to the board of county commissioners of the existence of the district. After December 31, 2025, if a political subdivision having ownership of the licensed ambulance service or a political subdivision responsible for the emergency medical service program for the service area exists, special taxes levied under this section and distributed pursuant to section 23-27-04.7 must be distributed to the political subdivision.