Okla. Stat. tit. 63 § 1-223
A levy of not to exceed two and one-half (2 1/2) mills on the dollar of assessed valuation of a county may be levied annually in accordance with the provisions of Section 9A, Article 10, Oklahoma Constitution, for the purpose of providing funds to maintain or aid in maintaining a county, district or cooperative department of health, where such levy is approved by a majority of the qualified ad valorem taxpaying voters of the county, voting on the question at an election called for such purpose; and the amount of the levy so approved may continue to be made annually until repealed by a majority of the qualified ad valorem taxpaying voters of the county, voting on the question at an election called for such purpose.
Okla. Stat. tit. 63, § 1-223