"the average annual wage for workers in Japan has been decreasing since it peaked in 1997. Statistics from the National Tax Agency shows that it fell by about ¥450,000 from 2001 to ¥4.09 million in 2011. This suggests that the decline in wage levels is responsible for the long period of deflation."
Source: EDITORIALS
Time for base wage increases
Japan Times
March 18, 2013