Following the 2000 census, the Oklahoma delegation to the U.S. House of Representatives was reduced from six to five representatives, each serving one congressional district. For the 112th Congress (2011–2013), there were no changes in party strength, and the delegation included four Republicans and one Democrat. In the 112th Congress, Oklahoma's U.S. senators were Republicans Jim Inhofe and Tom Coburn, and its U.S. Representatives were John Sullivan (R-OK-1), Dan Boren (D-OK-2), Frank D. Lucas (R-OK-3), Tom Cole (R-OK-4), and James Lankford (R-OK-5).