“Japan is the region with the richest poor people in the world. The average income of the poorest fifth of the population in Japan is at least 7 times more than that of the equivalent group in 8 other regions.” (Poorest Fifth - Worldmapper)
http://www.worldmapper.org/display.php?selected=151
物価水準もちがうので、これだけでどうこういえるものではないのだが、その点では相対的貧困率も似たようなものかと。