"The number of households (Japanese Customers) climbed to 51,950,504, up 4.8 percent from 2005 and topping the 50 million mark for the first time. But the average number of members per household hit a record low of 2.42. Single-member households stood at around 16.785 million, accounting for more than 30 percent of the total for the first time."
Source:Population stat positive, but via foreigner influx
Japan Times
Friday, Oct. 28, 2011