Ind. Code § 22-3-3-9
With respect to injuries occurring prior to April 1, 1951 causing temporary partial disability for work, compensation shall be paid to the injured employee during such disability, as prescribed in section 7 of this chapter, a weekly compensation equal to fifty-five per cent (55%) of the difference between his average weekly wages and the weekly wages at which he is actually employed after the injury, for a period not to exceed three hundred (300) weeks. With respect to injuries occurring on and after April 1, 1951 and prior to July 1, 1974 causing temporary partial disability for work, compensation shall be paid to the injured employee during such disability, as prescribed in section 7 of this chapter, a weekly compensation equal to sixty per cent (60%) of the difference between his average weekly wages and the weekly wages at which he is actually employed after the injury, for a period not to exceed three hundred (300) weeks. With respect to injuries occurring on and after July 1, 1974 causing temporary partial disability for work, compensation shall be paid to the injured employee during such disability as prescribed in section 7 of this chapter, a weekly compensation equal to sixty-six and two-thirds per cent (66 2/3%) of the difference between his average weekly wages and the weekly wages at which he is actually employed after the injury, for a period not to exceed three hundred (300) weeks. In case the partial disability begins after the period of temporary total disability, the latter period shall be included as a part of the maximum period allowed for partial disability.
IC 22-3-3-9