In contrast to job-hopping Americans, Japanese workers rarely jump to different companies, likely frustrating policymakers' efforts to drive wages up.

Wages fell steadily during Japan's long battle with deflation. Raising them has been a focus of Prime Minister Shinzo Abe's growth program, which seeks to "reflate" the economy through a cycle of higher corporate profits, worker pay and consumer spending.

Abe recently said changing the way Japan works is the biggest challenge in reviving the economy, and a lack of worker mobility is one reason economists say labor-market reform is badly needed. In economies with high mobility, such as the U.S., people readily change jobs to work in different companies, sectors and even regions offering higher pay.