The annual salary of each district judge is one hundred eighty-four thousand three hundred sixty-six dollars. Each district judge is entitled to travel expenses, including mileage and subsistence while engaged in the discharge of official duties outside the city in which the judge's chambers are located. The salary and expenses are payable monthly in the manner provided by law. A presiding judge of a judicial district is entitled to receive an additional five thousand one hundred sixty-two dollars per annum.