Traditionally, the income gap between the rich and the poor has been rather small in Japan, creating what has become known as the "all-Japanese-as-middle class" mentality.

During the 1990s, the aggregate income earned b the richest 10 percent of the population accounted for about 21.7 percent of nation's total income, compared with 25 to 30 percent in other industrialized countries.

The aggregate income earned by the poorest 10 percent of the population accounted for 4.8 percent of the total, much higher than the 1 to 2 percent in other nations.