The data from the previous link shows that Japan has increased from 11% part time workers in 1970 to 25% part time workers in 2022. It's entirely possible that

The data from the previous link shows that Japan has increased from 11% part time workers in 1970 to 25% part time workers in 2022. It's entirely possible that full-time workers are overworked while part-time workers are under-employed, leading to a decrease in average hours worked. Full-time workers can be time poor, while part-time workers may be money poor.