"This report presents a profile of the membership of the 114th Congress (2015-2016). Statistical information is included on selected characteristics of Members, including data on party affiliation, average age, occupation, education, length of congressional service, religious affiliation, gender, ethnicity, foreign births, and military service. [...] The portions of this report covering political party affiliation, gender, ethnicity, and vacant seats will be updated as events warrant. The remainder of the report will not be updated."
CRS Report for Congress, R43869
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html