The inflation-adjusted average monthly wage fell 0.9 percent from a year earlier in 2019, dragged down by an increase in part-time workers, the labor ministry said Friday.

Average monthly cash earnings per worker, including bonuses, fell 0.3 percent to ¥322,689 ($2,900) on a nominal basis, the first decline in six years, according to preliminary data by the Ministry of Health, Labor and Welfare.

The proportion of workers that are part-time reached a record 31.53 percent, up 0.65 percentage point from the previous year.

Average base pay and other scheduled wages fell 0.1 percent, to ¥244,485, while overtime pay and other nonscheduled cash earnings fell 0.8 percent, to ¥19,740. Bonuses and other special compensation payments were down 0.9 percent at ¥58,464.

Average monthly wages for full-time workers increased 0.3 percent, to ¥425,288, while those of part-time workers stayed flat at ¥99,758.

Workers put in 139.1 hours a month on average including overtime, down 2.2 percent from the year before, in a sign that government-promoted work reforms were resulting in longer holidays and less overtime work.

In December alone, average monthly pay including bonuses was flat on the year at ¥565,779. Inflation-adjusted pay was down 0.9 percent for the third consecutive monthly decline.