(a) Subject to the requirement of a referendum election as provided in this article, the governing authority of each county or municipality of this state, by ordinance or resolution enacted pursuant to the procedure set forth in this article, may adopt a local income tax at the rate of 1 percent upon the entire Georgia taxable net income as defined in Code Section 48-7-27 of every resident individual of the county or municipality and of every corporation and fiduciary with respect to that portion of its Georgia taxable net income which is reasonably attributable to property owned and business done by it within the county or municipality, to be determined in the same manner as otherwise provided in Code Section 48-7-31 for state income tax purposes.

(b) No individual whose gross income is less than $7,500.00 in any year shall be subject to any tax imposed pursuant to this article for such year.