Nonmarital Births: An Overview
http://fas.org/sgp/crs/misc/R43667.pdf
Explores the trends and reasons that nonmarital births are higher (41%) in the 2008-2013 period than formerly (28% in 1990 and 11% in 1970), discusses some of the characteristics of unwed mothers, and the role of cohabitation in producing more nonmarital births. From the Congressional Research Service, posted by the Federation of American Scientists