Whenever the chief justice appoints a district court judge of any of the various district courts of the State to serve temporarily as a circuit court judge of any of the various circuit courts of the State, the judge shall receive per diem compensation for the days on which actual service is rendered based on the monthly rate of compensation paid to a circuit court judge. For the purpose of determining per diem compensation in this section, a month shall be deemed to consist of twenty-one days. [L 1970, c 188, §12; am L 1975, c 58, §28; am L 1982, c 129, §27; am L 1986, c 128, §25; am L 1988, c 396, §2; am L 1990, c 72, §6; am L 1999, c 65, §7]