Updating in 2016.
More RepublicanR>90% = 2016
R>80% = 2012
R>70% = 2008
R>60% = 2004
R>50% = 2000
R>40% = 1996
R>30% = 1992
D>30% = 1988
D>40% = 1984
D>50% = 1980
D>60% = 1976
D>70% = 1972
D>80% = 1968
D>90% = 1964 or earlier
Virginia - 2008
Colorado - 2004
Nevada - 2004
New Mexico - 2000
Oregon - 2000
New Jersey - 1992
Delaware - 1988
Maine - 1988
Connecticut - 1984
California - 1980
Washington - 1980
Illinois - 1976
Vermont - 1976
Hawaii - 1972
Maryland - 1972
Massachusetts - 1956
New York - 1956
Rhode Island - 1956
District of Columbia - Never
More Democratic:D>90% = 2016
D>80% = 2012
D>70% = 2008
D>60% = 2004
D>50% = 2000
D>40% = 1996
D>30% = 1992
R>30% = 1988
R>40% = 1984
R>50% = 1980
R>60% = 1976
R>70% = 1972
R>80% = 1968
R>90% = 1964 or earlier
Iowa - 2012 (broke 16 year streak)
Michigan - 2012 (broke 28 year streak)
Minnesota - 2012 (broke 64 year streak!!)
New Hampshire - 2012 (broke 16 year streak)
Pennsylvania - 2012 (broke 68 year streak!!)
Wisconsin - 2012 (broke 16 year streak)
Ohio - 2004
Arkansas - 1996
Louisiana - 1996
West Virginia - 1996
Missouri - 1992
Montana - 1988
South Dakota - 1988
Tennessee - 1984
Alabama - 1980
Georgia - 1980
Kentucky - 1980
Mississippi - 1980
North Carolina - 1980
South Carolina - 1980
Florida - 1976
Texas - 1976
Alaska - 1964
Oklahoma - 1956
Arizona - 1948
Utah - 1948
Idaho - 1936
North Dakota - 1936
Nebraska - 1932
Indiana - 1924
Kansas - 1916 (century streak)
Wyoming - 1916 (century streak)