The number of non-regular (contract or part time) workers in Japan increased from 15 to 33 percent between 1984 and last year. Jeff Kingston of Temple University, Japan Campus, said the expansion in non-regular workers is a product of two decades of corporate cost cutting, coupled with ageing baby boomers who are becoming increasingly expensive because of Japan's seniority wage system. "I believe they felt they owed these people. But they needed to fund that and it came at the cost of young workers," he said.