The make-up of the United States House of Representatives every two years since 1789. The last Congress included is the 112th Congress, which completes its term in 2013.
congress - The number of that year's Congress
yearStart - Starting year
yearEnd - Ending year
seats - Total number of seats
p1 - Name of the first political party
np1 - Number of seats held by the first political party
p2 - Name of the second political party
np2 - Number of seats held by the second political party
other - Other
vac - Vacancy
del - Delegate
res - Resident commissioner
Source
Office of the Clerk of the U.S. House of Representatives Party Divisions: http://clerk.house.gov/art_history/house_history/partyDiv.html Data for Congresses 1-111 was recorded from the website above on November 1st, 2010. It appears this page was later moved to http://artandhistory.house.gov/house_history/partyDiv.aspx (no longer available) where data for Congress 112 was recorded on April 21, 2011.
Use the following R code to directly access this dataset in R.