Among the most striking features of family household composition is the progressive decline in the average size of households and the rapid rise in one-person households.
In the United States, for example, single-person households as a share of total households rose from 13% in 1960 to 28% in 2011, and the number of lone parent (primarily single-mother) households increased from 1.5 mil in 1950 to 9.5 mil in 2000. In Japan, the share of one-person households rose sharply from 19.8% in 1980 to 29.5% in 2005.
But, it is Scandinavians who seem most lonely with one-person household representing nearly every second family in Sweden, for instance.
More details at One-person Household Statistics