Salary and expense allowances of legislators. 2-4-2. The salary of each member of the Legislature is equal to one-fifth twenty-5 two percent of the South Dakota median household income for the most recent year for which data is available, as reported by the United States Census Current Population American Community Survey, as conducted by the United States Census Bureau, and ascertained and adjusted each year by the State Board of Finance to take effect on the first day of January of each year for every regular legislative session. In addition, each legislator member shall receive: (1) Reimbursement to be paid after the regular legislative session for actual mileage or its the equivalent traveled to and from home home, not more than once each weekend or between days of recess during the regular legislative session, at the rate set pursuant to § 3-9-1; (2) Expenses of one hundred twenty-three dollars per day for each day of a regular or special legislative session as prepaid reimbursement for living expenses, including meals and lodging, laundry, cleaning and pressing of clothing, and all other uncompensated expenses expenses, as defined in § 2-4-2.1 2-4-2.1, incident to the performance of legislative services, or at the amount fixed for the per diem allowance that is authorized by the United States Internal Revenue Service to be excluded from the gross income without itemization as of October first each year, whichever of the two is greater; and (3) Five cents once each regular or special legislative session for every mile of necessary travel in going to and returning from the place of meeting of the Legislature by the most usual route. For each day's attendance at special sessions, each member, in addition to mileage and expenses, shall receive a per diem calculated by the director of the Legislative Research Council equal to the normal daily compensation for the regular session immediately preceding the special session. 4