290.502.  Minimum wage rate — increase or decrease, when. — 1.  Except as may be otherwise provided pursuant to sections 290.500 to 290.530, effective January 1, 2007, every employer shall pay to each employee wages at the rate of $6.50 per hour, or wages at the same rate or rates set under the provisions of federal law as the prevailing federal minimum wage applicable to those covered jobs in interstate commerce, whichever rate per hour is higher.

  2.  The minimum wage shall be increased or decreased on January 1, 2008, and on January 1 of successive years, by the increase or decrease in the cost of living.  On September 30, 2007, and on each September 30 of each successive year, the director shall measure the increase or decrease in the cost of living by the percentage increase or decrease as of the preceding July over the level as of July of the immediately preceding year of the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W) or successor index as published by the U.S. Department of Labor or its successor agency, with the amount of the minimum wage increase or decrease rounded to the nearest five cents.

  3.  Except as may be otherwise provided pursuant to sections 290.500 to 290.530, and notwithstanding subsection 1^* of this section, effective January 1, 2019, every employer shall pay to each employee wages at the rate of not less than $8.60 per hour, or wages at the same rate or rates set under the provisions of federal law as the prevailing federal minimum wage applicable to those covered jobs in interstate commerce, whichever rate per hour is higher.  Thereafter, the minimum wage established by this subsection shall be increased each year by $.85 per hour, effective January 1 of each of the next four years, until it reaches $12.00 per hour, effective January 1, 2023.  Thereafter, the minimum wage established by this subsection shall be increased or decreased on January 1, 2024, and on January 1 of successive years, per the method set forth in subsection 2^** of this section.  If at any time the federal minimum wage rate is above or is thereafter increased above the minimum wage then in effect under this subsection, the minimum wage required by this subsection shall continue to be increased pursuant to this subsection ^***, but the higher federal rate shall immediately become the minimum wage required by this subsection and shall be increased or decreased per the method set forth in subsection 2^** for so long as it remains higher than the state minimum wage required and increased pursuant to this subsection.

  4.  For purposes of this section, the term "public employer" means an employer that is the state or a political subdivision of the state, including a department, agency, officer, bureau, division, board, commission, or instrumentality of the state, or a city, county, town, village, school district, or other political subdivision of the state.  Subsection 3^**** of this section shall not apply to a public employer with respect to its employees.  Any public employer that is subject to subsections 1^* and 2^** of this section shall continue to be subject to those subsections.