A new report from the Congressional Research Service (CRS) presents a profile of the membership of the 115th Congress (2017-2018) as of January 3, 2018. 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 report can be obtained at https://fas.org/sgp/crs/misc/R44762.pdf.