(a) The board may impose an annual tax at a rate not to exceed the limit approved by the voters at the election authorizing the imposition of the tax.
(b) The tax rate on all taxable property in the district for all purposes may not exceed 75 cents on each $100 assessed value of the property according to the most recent certified tax appraisal roll of the district.
(c) In setting the tax rate, the board shall consider the income of the district from sources other than taxation.