The Basic Survey on Wage Structure distinguishes regular employees from part-time workers, such as non-regular employees. Based on this, real hourly wages -- a term closer to real wages per employee -- are calculated.
The estimation shows that real wages for regular employees hired for an indefinite period rose by 4.5 percent from 2012 to 2019, and those for non-regular employees (among part-time workers) increased by 8 percent during the same period. For details, see Iwata, K., "Nihon-gata kakusa shakai" kara no dakkyaku (Tokyo: Kobunsha Shinsho, 2021), pp. 192-3.