The board of freeholders of the county or other body having control of the finances thereof, shall include annually in the tax levy the amount of money needed for mosquito control; but in no year shall the amount so raised exceed the following amounts:
a. In counties where the assessed valuations are not more than $25,000,000.00, a sum not greater than one mill on every dollar of assessed valuations.
b. In counties where the assessed valuations are not more than $50,000,000.00, a sum not more than one-half of one mill on every dollar of assessed valuations.
c. In counties in which the assessed valuations are in excess of $50,000,000.00, a sum of not more than one-quarter of one mill on every dollar of assessed valuations.